Derek still got nightmares about Boyd. Still woke up in the middle of the night covered in sweat with shaking hands and a pounding heart. He still stared down at his trembling hands into the early hours of the morning, wracked with guilt as his body shook with sobs for the boy who died. The boy who deserved better and was his responsibility.

It didn't happen often; just enough to remind Derek of what he'd done and how wrong he had been to think he could keep those kids – his betas – safe. When Erica died, Derek felt like a piece of himself had died too. And when his claws had pierced Boyd's stomach, Derek felt like he was going to vomit because god no please I can't lose anyone else. He tried to stop the bleeding as best he could but it wasn't working and all he was doing getting more blood on his hands.

"It's okay, it's all okay"

But it wasn't, none of it was okay because for months after that night, Derek couldn't look at his hands without seeing the blood, without seeing Boyd's bleeding body and lifeless eyes. He barely slept because he knew if he did, he'd see Boyd and Erica's faces again, reminding him of how badly he'd failed these kids who believed that he could keep them safe.

Stiles noticed the heavy bags under Derek's eyes like Stiles notices everything. He tried to get Derek to talk to him but all it summoned was a dark glare and a sharp 'leave it alone Stiles.' Stiles hadn't felt so helpless since his mom had died and he hated it because Derek wasn't even his friend but the pain in his eyes whenever Boyd and Erica were brought up made his chest tighten and his heart drop into his stomach.

Isaac used to hear him and stand at the bottom of the stairs, just looking at Derek with sad eyes. Nowadays though, he stays in his room when he hears Derek crying because he knows his presence just makes it worse and there's nothing he can do to lessen the guilt weighing on Derek's heart.