I (16F) was playfully looking through my bf(17M)'s previously downloaded apps, when I found some goofy gooner game. I wasn't upset by it at all, I just found it funny that he'd downloaded that before and started laughing. He immediately got mad and started justifying it saying he didn't remember downloading it, but I was laughing too hard to really react (keep in mind this all happened within the span of a few seconds). While I was laughing, he hit his head hard on my wall, which immediately made me stop laughing. It kind of triggered me, since I've told him that I do that often to self harm. I went quiet because I was upset. I handed the phone to him and quietly told him I was sorry, laying my head down. I was upset because I didn't mean to make him mad, I was just joking around and I didn't realize it was that serious to him. This is messed up, but due to past relationship experiences, I almost believe it could've been a manipulation tactic, but I accept that either way, he harmed himself over something small, and that's not okay. So, AITAH for being upset at him for overreacting?