Heat pours over John and he can't even breathe, the blazing air scorching his lungs and his mouth and crackling across his face. The thump of the blast shatters all other sound out of the air; he can just barely catch whispers of "Medic" that he knows are probably screams and cries, but his shoulder is gushing blood and twitching and his vision's going dark. He opens his mouth to cry out, to call for himself, but the air is thick and burning and tears apart his throat and he feels a clench in his lungs, a squeezing, all his breath is gone, and John Watson knows with absolute certainty that he is going to die, and the last thing he remembers is seeing the sand turn hideous and maroon with blood.
—-
He wakes in a haze, the air fulls of sand and panic, and only half-sees and hears what they tell him. Nerve damage and loss of blood and infection and other words that don't mean anything, and he swims in and out on a haze of fear and drugs and more fear, and when he wakes in the middle of surgery he screams, the only time John Watson has screamed in pain in his adult life. They dig out the necrotic flesh, the muscle and tissue killed by what he later learns was a vicious strain of MRSA, and he feels it, he feelsit and screams and everything goes dark again and the last thing he remembers is the taste of copper pouring into him as his throat bleeds with his scream.
—-
That scar will never, ever fade, and will never be the kind that lovers linger over. It will never look decent or exude heroism or make people admire him. It will be ugly and lumped and red and angry, forever, and John Watson hates it more than anything else about himself — and that list was long enough already, before the war and the blood and the dreams. The scar intrudes, makes things difficult. He never bares his upper body to others, ever. He never talks about or shows anyone or even looks at the scar after that first terrifying look just after surgery. The last thing he remembers about the scar is the way it had felt the first time he'd showered on his own: the lumps and tendrils and strange shiny smoothness of it had startled him, he'd nearly fallen, and had never touched it again.
—-
Sherlock asks about being wounded, and John, still riding on the high of the kill or the rescue or the way the detective's face lit up, manages to answer evenly and without fear. As they walk, he isn't even thinking about it, which means that he misses the way Sherlock keeps peering at his left hand and arm. He isn't psychic, so he doesn't read Sherlock's thoughts as the detective puzzles out most of the physical damage from movements and unconscious compensations and John's grip on his fork. He's not an expert in Sherlock just yet, so John Watson doesn't realize just how keen the taller man's interest is in whatever happened to that shoulder, nor does he hear the unspoken interrogation bubbling behind Sherlock's lips: what kind of bullet in what kind of gun, what was the scenario, where exactly were you, what was the treatment regimen, why won't you tell me anything about the war.
—-
The first time he and Sherlock fuck, John keeps his undershirt on, as usual. It's not a problem or even noticeable, a tiny fact lost in the hurricane of their hurry and desperation, mouths tearing at each other, not even time for Sherlock to shed his trousers completely, scrabbling fingers with lube and condoms, gasping instructions and encouragements between moans. As John slides into him, one of Sherlock's hands drifts across the cloth-hidden scar and pauses, and John nearly leaps out of his skin; shakes off Sherlock's hand, buries his mouth on Sherlock's neck, and the detective is sufficiently distracted not to ask annoying questions. And when they finish, panting and spent, John excuses himself and washes up, comes back swaddled in a battered old jumper, thankful for the excuse of the freezing room to deflect Sherlock's inquisitive nature. John Watson does not want to lose whatever this is or could become, and he realizes suddenly that he really has developed something of a complex about the scar.
—-
"Let me see it." Sherlock isn't trying to be demanding, not really, he's just curious like a child with a wrapped present and poor impulse control.
"No." John won't look at him.
"Guilt, and shame, so it's ugly. I don't care, John, I'm sure we're sleeping together regularly enough now for you to know that I find you attractive." Said like a man who has never doubted his own beauty, nor his own ability to get what he wants. "Let me see."
"No, Sherlock." John Watson manages not to storm out of the room, but only just. If it weren't for Sherlock's fingers scratching deliciously in the short hairs on the nape of his neck, he would already have run away. This is the fifth iteration of this conversation in four days, and his nerves are dancing on razors now.
"Why?" Sherlock is whinging, and John wants to punch him, really, or go shoot something in the summer sun for a while. If Sherlock notices the doctor's gun hand twitch involuntarily, he says nothing about it.
"Because I don't want to, all right?" John feels the flush creep up his neck. "I don't want you to see it, and I don't want to see it, and I don't want you to touch it, and I don't want to touch it. Just," he heaves a sigh. "Just leave it, Sherlock, please."
—-
"What do you want for your birthday, love?" John's happy and relaxed, snuggled in an afghan with a mug of cocoa. It's just after their second Christmas together, and Sherlock hasn't asked about the scar in a month and a half, and sometimes John Watson is so happy he can barely breathe.
Sherlock isn't facing him, is peering into a microscope, when he answers, "To see your scar."
"Fuck off." John storms out of the room.
Sherlock appears in John's room a week later. "I apologize, John." He really does look ashamed, even remorseful, and so John kisses him as a gesture of acceptance.
"Why are you so interested in it, anyway?"
"When we're having sex, you keep it hidden: an undershirt, or an open button-down, or a jumper. You never bare your upper body, not even in the summer when you're broiling hot. And when I touch your shoulder, you jerk away or try to distract me. You won't let me shower with you, likely because you know I'd be able to see it. It's the only part of your life you really hide from me, John, it and the war, and I'd like to know about it. About you." Sometimes, rarely, Sherlock's face turns open and honest and more human. This is one of those times, and John is powerless against the knowledge that he does that to Sherlock, that Sherlock cares about him.
"I'll show you, sometime, Sherlock, I promise. But not…not right now, all right? I can't, yet. Do you understand?" Sherlock nods, and John continues. "But I promise, I will show you sometime."
—-
They have been together for three years, eight months, two weeks, and five days when John Watson shows Sherlock the scar.
First, though, they have a long, languid session of sex, during which John kept his shirt on as usual. As they lay tangled together, soft and relaxed and drifting on the afterglow, John props himself up on his good arm, gazing down at the man he loves.
"We were in Afghanistan, as you know. I'm honestly not sure where exactly, somewhere between Kandahar and the border. And I don't even remember much of it: the explosion and the concussion did a number on my memory. From what I know, we were hit by an IED and then picked off by a sniper. Three men lived through it: me, an American man I didn't know, and Yasir, our translator." John says all of this in a low monotone, as if he's reciting from field notes. Sherlock's eyes trace his face, but do not waver. "The field hospital there was…well, it was shit, to be honest, and an infection got around and we all got sick. The American died in hospital and Yasir lost a leg, and I got the scar. They had to dig out infected tissue because the drugs weren't doing a thing—"
Sherlock interrupts for the first time. "MRSA?"
A nod. "And that's the story, Sherlock. It's not pretty, and it's not sexy, and it's really not that interesting."
"Have you ever seen it?"
"Once, just after surgery." A mirthless grin stretches across his face. "I was the only one in the whole bloody place qualified to say whether they'd gotten all of the infected tissue, see. So I had to examine my own wound. And tell them that they'd missed some bits." John chuckles, and if Sherlock was the kind of person who prayed, he'd pray to never hear that sound again.
"I understand your point, John," Sherlock says softly. "I assure you, I have seen worse and done worse myself."
"All right then." John pulls the shirt off his back and turns away from Sherlock, lying on his stomach to offer the best view.
It's not pretty, and it's not sexy, and Sherlock is momentarily stunned. He'd not known about the infection, and so had extrapolated based on percentages dealing with the initial facts (almost certainly a bullet from an AK-47, in the muscle of the left shoulder, in a spot that left permanent and slowly worsening nerve damage severe enough to end John's ability to perform surgery well enough to keep his old job). This sprawling, lumped destruction is far worse than even the worst-case scenarios he'd developed.
The initial scar from the actual bullet is huge, a starburst of shimmering tissue. Worse than that are the scars left from the infection: angry, fat lumps exploding into ropes and tendrils of raised lines across the arch of John's shoulder blade and down to the top of his ribcage. They're dark and crabbed and uglier than Sherlock could have imagined, and he suddenly understands exactly why John has developed the complex about it. For a moment he is frozen with fear: he cannot ruin this, cannot break John's fragile trust in him.
When John feels Sherlock's lips press to the central wound, the initial bullet hole, he starts. It's not very sensitive, the nerve damage saw to that, but it hasn't been touched by anyone, and especially not by a pair of soft, kind lips. Sherlock kisses each lump of scrawling fibers, trails kisses along the lines emanating across much of John's left side, presses his lips to the ravaged skin again and again until John is weeping silently into the pillow.
Sherlock pauses, a thrill of fear in his belly — what if he misjudged, what if his shaky hold on social norms failed him, what if, what if, what if.
John turns, pulls that dark, curly head to him, kisses him soundly. "You've become a good man," he says against Sherlock's mouth, "a good man, through and through."
"I love you," Sherlock whispers in return, "every stupid perfect inch of you."