Dean gripped the blade in his hand. Being back here wasn't right. He shouldn't be here, he didn't deserve to be here. Guilt ripped through him as he remembered the pain on the countless faces he tore into whilst in Hell. They begged him to stop, screamed it at him. Alastair would sit in the corner, watching him, forcing him to push the blade into them deeper, to watch their blood run down to his fingertips. Alastair wanted to train him, said he had potential. He wished he was stronger. He waited for the day where he would be ready to get back on the rack. God, he wished he wasn't so weak.
He remembers the day he stopped. He screamed at Alastair, refused to hurt more people. All Alastair did was smile. He knew what was in Dean Winchester's head. He didn't want to hurt people, he didn't want other people to hurt him. How pathetic.
As Alastair brought another young lady in, ready for Dean to tear into her, Dean spoke.
"I could do it to myself."
That's when Dean became Alastair's favourite. Watching Dean torture himself was far more entertaining for him. Dean winced as he cut down to the bone in his thigh. Cutting to the bone was enough for Alastair the first time, but gradually he wanted more.
Dean was disgusted with himself. He hated that he'd grown to like the feeling. He even craved it sometimes. Being able to hurt himself wasn't becoming torture for him anymore. Alastair was intrigued by this, urging Dean to continue. When he would be healed after each day, Alastair would make sure to leave the scars. He felt a twisted sense of pride in Dean when he stared at his own skin.
After years and years of carving into old scars something changed. He felt an unfamiliar pain on his shoulder and he was encircled by darkness.
Finding out you were pulled out of hell was one thing, but finding out an angel pulled you out was overbearing. How could his soul be so special that an angel was sent to bring him back. Especially Dean's.
Sam understood that Dean had been through a lot, but he would never know the extent. He doesn't know how hard it is for Dean to keep it together. To not lose it whenever he sees his unmarked skin. He can't stand being so clean. Having no scars. He needs to see blood, the skin being torn apart.
And that leaves him in the bathroom of the hotel he was staying in with Sam, holding the knife and deciding whether to cut his thigh or his arm.
He decides on his thigh, and positions the knife, pressing down and slicing through his flesh. He can't do much since it won't heal by the end of the day, but it's enough for now. He's never had to clean up the blood before and it's a difficult task. He hopes that Sammy doesn't notice anything.
But it's not Sam he has to watch out for.
Cas has been visiting them more frequently, he is kind of a good friend of the brothers now, checking in with them often, especially with Dean.
Sam's out on a food run when Dean and Cas are at the motel. Dean's in the kitchen when Cas coughs, getting Dean's attention.
"Dean, is it alright if I ask you a question?"
Dean says sure. Cas was so clueless about humanity, he probably had thousands of questions circling round his head. But the one he asked was a shock to Dean.
"Why do you hurt yourself? Like you use to when you were with Alastair?"