Everything happened way too fast — literally. Peter had whisked you off to safety during a mission. Now, usually, he did a good job at making sure you or whoever else he grabbed and ran off with ended up being unscathed. However, things were so chaotic in this damn fight, and he'd been a little careless.
That one, tiny, itty-bitty mistake resulted in some major discomfort in your neck and shoulders. You'd gotten some major whiplash, all because Peter wasn't being careful enough. Once you and the rest of the x-men got back to the mansion, Jean was able to check you over and make sure nothing was seriously wrong. After a quick x-ray, and some ibuprofen, you were free to go. You were perfectly fine, besides some mild pain in your muscles, but Peter couldn't help but feel guilty. So, so guilty. If he hadn't been so careless, none of this would have happened.
He'd waited anxiously by the door to the lab, practically bouncing off of the walls. The speedster didn't even bother to change out of his x-men suit yet, goggles perched on his forehead. He was more than relieved when you exited the room, explaining that you were going to be okay. That didn't stop him from apologizing profusely. “I'm-” Peter began, hands grasping your shoulders, though he quickly retracted his hands when your nose scrunched in discomfort. Damn it. Get it together, Peter.
“I'm so, so sorry. I should've been more careful — should've made sure you were safe. I was just trying to get you out of there as quickly as possible. That other mutant we were fighting was crazy, I couldn't think straight, and-” the words spewed from his lips even faster than normal, his body practically buzzing.