This is a slightly edited and expanded fill, originally written for this prompt at tfa_kink: The worst thing, Finn is sure, that he will ever witness, is seeing Poe Dameron cry.
This focuses less on the crying than I intended. There's also a slight—very slight—implication that Finn might be Force-sensitive.
Title from "I Won't Let You Down," by OK GO.
Finn blinks his eyes open slowly. A flood of sensation sweeps over him then: bright twinkling lights and droning fuzzed out sound and way too much feeling and—Vader's tits—everything aches. He tries to push himself up into a sitting position but pain lances through his back like short, sizzling stabs of a 'saber blade and he flops back down on the hard slab of a mattress that's apparently been acting as his bed for however long he's been out. Finn feels sweat break out across his forehead and over his upper lip and under his arms, and he clenches his hands into fists in an attempt to stanch a nearly crushing wave of nausea.
[DESIGNATION:FN-2187, YOU ARE AWAKE.] A metallic voice starts screeching rather too close to his ear and Finn resists the urge to reach out and throttle the droid that voicebox belongs to.
"Name's—ah, kriff—name's Finn," he gets out through gritted teeth and a clenching jaw. If he clenches his jaw any harder his teeth'll probably shatter. Under the thumb of Hux and Phasma and Kylo Ren—Finn suppresses a shudder—something like that was enough to get one tossed out of the airlock. The Order, but those three especially, generally didn't have much patience for anything that wasn't in pristine, working condition. He's lucky he got as many chances as he did before—well, before Poe.
[DESIGNATION:FINN,] the medidroid corrects itself in a blessedly less screechy, still irritatingly metallic—still unfortunately close to Finn's ear—voice. [DESIGNATION:COMMANDER-POE-DAMERON-BEST-FREAKING-PILOT-IN-THE-GALAXY HAS BEEN SENT OFF FOR THE EVENING AS VISITING HOURS ARE OVER, BUT HE LEFT DESIGNATION:BB-8 TO MONITOR YOUR PROGRESS. DESIGNATION:BB-8 WILL TAKE CARE OF ANYTHING IN WHICH YOU'RE LACKING.]
BB-8 rolls up to Finn and butts into his calf, affectionately, or as affectionately as a droid can. Finn pats its shiny dome and the astromech chirps at him.
"Poe was here?" he asks the medidroid, as he runs his fingers lightly over BB-8's glossy metal dome.
[DESIGNATION:COMMANDER-POE-DAMERON-BEST-FREAKING-PILOT-IN-THE-GALAXY HAS BEEN AT YOUR BEDSIDE AS HIS SCHEDULE ALLOWS,] the medidroid responds, as it flicks out some ominous looking pincers and tugs at the front of Finn's medbay gown. [WOULD DESIGNATION:FINN BE IN FAVOR OF A SONIC SHOWER AND A FRESH CHANGE OF CLOTHING?]
Speaking of clothing... "Hey, where's my jacket? The one I came in wearing," Finn says, gently brushing the medidroid's pincers away from his nipple.
[WE DO NOT KNOW THE WHEREABOUTS OF DESIGNATION:COMMANDER-POE-DAMERON-BEST-FREAKING-PILOT-IN-THE-GALAXY'S JACKET—]
"You know," Finn interrupts, unable to help a grin, "you could just call him Poe Dameron like the rest of us."
[WE DO NOT BELIEVE THAT WOULD BE POSSIBLE AS DESIGNATION:COMMANDER-POE-DAMERON-BEST-FREAKING-PILOT-IN-THE-GALAXY'S DESIGNATION HAS BEEN HARDWIRED INTO OUR MAINFRAME AND IT IS IMPOSSIBLE TO OVERRIDE A MEDIDROID,] it says, letting the pincers drop with a gentle whirr. [WE WILL TAKE YOU TO THE 'FRESHER FOR A SHOWER NOW, DESIGNATION:FINN. YOU REEK.]
Finn rolls his eyes at that. "Lemme guess, Poe programmed you himself?"
[AFFIRMATIVE,] says the medidroid, scooting away from the edge of the bed so Finn can get up and swing his legs over the side.
Finn glances down at BB-8, who—which?—tilts its dome up until they meet eye-to-visual-sensor. "I'll be fine, BB. You can go back to Poe," he says.
BB-8 chirrups skeptically at him and swivels its dome in what Finn takes to be a headshake.
"Suit yourself," FInn says, though he doesn't really mind. BB-8 just rolls over to a sleek black chair and begins nudging it next to the bedside.
Finn slides carefully off the mattress and lets the medidroid lead him to the 'fresher. He doesn't need to tell it that he can shower by himself. It closes the 'fresher door behind him and rolls off to find Finn some clothes.
When Finn emerges from the shower, he finds a folded olive-drab tunic, tan pants, and a familiar weather-beaten brown jacket waiting for him on a chair. Finn dresses as hastily as he can, mindful of the bandages running diagonally across his back, and the tender, raw, throbbing scar underneath.
Finn tugs the jacket on slowly, savoring the slide of his arms through the sleeves. It just feels so right. He never had anything of his own as a 'trooper, least of all a jacket like this one. This jacket, even with the jagged gash splitting the back, is the best armor he could have ever had, way better than any white plastoid shell.
Once he's done, Finn rushes out of the 'fresher, eager to collect BB-8 and get a move on. He's not in the best shape he's ever been in—the medidroid had let it slip that Finn was in a medically induced coma for nearly three weeks and his muscles had atrophied a bit—but he's regaining his strength rapidly. If he didn't know any better, he might think it's the Force at work, knitting his body back together.
When he gets back to the medbay, to the room that had been his home for nearly a month, neither BB-8 nor the medidroid are anywhere to be found.
But Poe Dameron is. He's pulled up a chair next to Finn's empty bed and his forehead is resting against the metal bedrail. Finn isn't sure if Poe's sleeping or not, so he approaches him from behind, with light footsteps. He reaches out carefully, slowly, tracing his fingertips over Poe's hunched shoulder.
"Blessed stars!" Poe startles, arms and legs flailing, and he spills out of his chair, landing on the floor with a metallic clatter and a heavy thump.
Finn looks down at him and tries not to laugh. It'd be awful rude. Then he gets a good look at Poe's pale face, the deep, dark bags under his eyes, and his wet, shiny cheeks.
"Poe?" Finn holds out his hand to him and Poe accepts, letting Finn haul him to his feet. "Are you...are you okay?"
Poe swipes his sleeve across his face and snuffles into the coarse olive-drab material. "I... Yeah, buddy, I'm fine. I came in and saw the—and I just assumed—"
"Assumed what?" Finn asks. When Poe moves to pull his hand free, he lets him, but something cool and liquid swoops through his gut.
"Couldn't find you or MD-2880, and I assumed the worst. I sent BB to go look for..." Poe trails off with a sigh, and shudders a full-body shudder, as if he might just collapse to the ground like a pile of empty robes. Finn reaches out and grasps Poe's shoulder, anchoring him. "I'm really glad you're awake, buddy. Really glad."
Finn squeezes Poe's shoulder gently. "MD-2880 took good care of me." He pauses, takes in Poe's glassy eyes and the raw redness of his cheeks. His hair is disheveled, dirty, and damp curls cling to his forehead and the sides of his face. Finn's fingers itch to push the hair back into place. "Let me take care of you."
"Buddy, I'm fi—"
"You look like Bantha dung," Finn interrupts and flushes with pleasant warmth when the crack gets a smile out of Poe.
"I should be the one taking care of you," Poe says. "You need to be evaluated and properly discharged. And you haven't had a real meal in weeks. You're probably starving."
Finn tilts his head and considers this. Maybe the cool swoop he felt in his gut at the sight of Poe's exhausted form slumped across his hospital bed was just hunger. "I am," he agrees. "This doesn't mean we shouldn't...take care of each other. I'll take care of you and you'll take care of me."
Poe fights gamely against a smile that threatens to take over his entire face, but he loses in the end, and it's a glorious sight.
It's an imperfect smile, Finn thinks, with his crooked teeth. Maybe the Order would have had the offending teeth yanked out and replaced with hollow ceramic capsules they could use to store poison or datachips. Maybe they'd have even tossed him out of the airlock for it. But Finn can't picture Poe with any smile but this slightly imperfect one, and it warms him over to think that he's the one that put it on his face. Poe's eyes no longer appear glassy or haunted, and the tears have dried on his cheeks.
"I like the sound of that," Poe says, reaching up and cupping Finn's cheek in his palm. He lets his hand drop too short a time later, trailing his cool fingers down in a slow—familiar—swooping motion and Finn tries to follow after his hand. "Let's get some food in you. That all right with you, buddy?"
"It's all right," he says, trying to fight the knot of disappointment that threatens to rise in his chest up to his throat.
Poe groans and drags a hand through his curls and down over his face. "Then we can talk about...all of this."
He leans in a bit and stops, and for a moment Finn wonders if he was going to kiss him but then thought better of it. The tip of Poe's tongue peeks between his lips and darts back into his mouth to run over his teeth. Finn tracks the movement, wishes that mouth and that tongue were a little closer to his own. Then Poe leans in all the way and presses a light, barely-there kiss to the corner of Finn's mouth. If Finn hadn't had his eyes open the whole time, he probably would have missed it.
"Okay," he exhales, when Poe steps back and gives Finn some space. "Okay."
Poe's face breaks into a big grin that reaches his eyes. It reminds Finn of the suns and stars and planets he saw in his days aboard the Finalizer, filling him with the same breath-stealing, expansive wonder. He thinks he'd give up every one of those suns and stars and planets for Poe to look at him like this for the rest of his life.
Finn reaches out and catches Poe's hand in his, and the two of them leave for the mess hall.