A/N: The prompt for this story was "hugs."
The panic attacks that plagued Stiles after his mother's death started again when Scott turned, when things started getting weird, when they started getting dangerous, but everyone was too pre-occupied in their own lives, or in the lives of everyone else, that they didn't notice. Except for Derek.
Derek noticed everything about Stiles, and it didn't take long for him to realize that when things got scary, no matter how brave he acted, his heart was thumping, racing, and while he tried to keep a level head, even in the most terrifying of situations, some physical and chemical part of him was fighting those decisions and actions with all their might, trying to trap the boy in a world of panic and terror.
Derek noticed how strong Stiles was to fight through that on his own, to brave the boy had to be to power through these things, even with every part of him trying to stop him. His body was trying to reduce him to a fearful, shaking, ill mass, but Stiles refused to let himself fall prey to that, and Derek was the only one who saw.
Sometimes, after a rough event, a rough day, Derek would follow Stiles home, he would sit outside the boy's window, hiding in the shadows, just for long enough to make sure that Stiles was alright, and after an hour or two, he always was. Shaken? Maybe, but alright? Every time. Except once. Another wolf had had his claws at Stiles' neck, only seconds away from ripping out his throat, and despite Stiles' claims that he was fine, as Derek sat under his window, he could sense the panic still more than present in the boy…and this time, it wasn't going away.
After one hour, Derek felt bad. He knew that, if it weren't for him, if it weren't for all of this wolf stuff, Stiles' biggest concern would be the chem test on Friday, or whether or not he would have a date for winter formal, not whether or not he was going to live to see the next day, whether or not his loved ones would.
After two hours, Derek felt guilty. He hadn't been the one to bite Scott, the one to drag Stiles into all of this, but he had stolen Scott's only chance at a cure, and Stiles' only out of this terrifying world. He was too loyal to leave Scott to suffer on his own, but he was too human to handle stress that only someone with superhuman traits would ever be able to cope with alone.
After three hours, Derek was just plain worried. It had never taken this long before, and that was too much for him. He scaled the wall and tumbled in Stiles' bedroom. The boy was sat on the floor, his back pressed to the wall in the corner of the room, his knees pulled to his chest, his whole body trembling.
"Go away," he whispered, not even looking up, assuming that the figure in his room was Scott. He didn't want Scott to see him like this, to know what kind of a toll this life was taking on him.
"I can't do that." Derek walked over to him and slid down the wall next to him, putting his arms around Stiles, pulling him into a hug. "I can't just sit by anymore and watch, listen, feel while you suffer so much for the wellbeing of others."
"I'm fine," Stiles stated, though he didn't pull away from the embrace.
"No, you're not." Derek shook his head. "You're taking on the responsibilities of others, taking care of others, and not yourself. You think no one sees it, but I see it. I see the way you struggle every day to keep these feelings down, to keep the panic from crippling you, and I see the way that it consumes you when you come home and think no one knows just how hard this really is."
"It's fine," Stiles mumbled. "There are bigger problems out there, there are-"
"There are other problems," Derek cut him off. "But that doesn't mean they're bigger or more important than you." He began to rub Stiles' back, and the boy felt the panic inside of him begin to subside, a combination of the backrub and comforting, strong embrace, calming him down.
Now, whenever Derek senses the panic rising in Stiles, he goes to him, puts his arms around him, and hugs him. No matter where they are, no matter what's happening, as soon as he gets to Stiles, he holds him, and Stiles feels safe in that embrace, whole and comforted in ways he never had before. They don't exchange words, they don't have to. Derek hugs him, and the pain goes away. They both know it, and they both let it hang there, between them, developing slowly, because these things take time. For now, all that matters is that no matter how keyed up Stiles gets, Derek is always there for him, to calm him down, and make him feel at ease.