⚠️ SELF HARM MENTION ⚠️
Midoriya: Panic. He won't know what to do when he eventually finds out. He'll start asking questions and will want to get an adult for help. Even if you don't want him to, he's going to do what he thinks is right, even if it means betraying your trust in him.
Bakugo: When he finds out, he will be really angry, but mostly at himself for not noticing. He confiscated any and all items that you possibly use to harm yourself and watches over you every night. He won't tell a teacher unless he thinks you'll really hurt yourself more than you already have.
Kirishima: He will comfort you as best he can and try to understand your situation. He gives you more attention than usual just to make sure you don't feel bad and harm yourself again. He tells you that if you get the urge to do it, just go to his room and he'll stay up with you until the urge passes.
Denki: He will kiss every scar, every cut, every bruise. He will cry. He won't know what to do, but seeing you in pain (especially silent pain) hurts him so much. He wants to tell a teacher but you convince him not to. He does his best to understand you and will go to the lengths of even anonymously asking for advice on the internet.
Todoroki: He's going to be very upset. He's worried and being frantic but in a calm way. He questions you, but if you don't want to open up, he'll drop it. He has to tell the teacher. He cares too much to let this go.
Iida: Rambles about how self harm is, well, harmful. He takes you to Recovery Girl even if he has to force you. There is no bargaining with him. He will always put you above anything else.
Aoyama: I genuinely feel like he would not hesitate to tell the teacher. He would probably notice after walking past his seat a few times. Maybe it's the way you're dressed that day or the way you're limping, whatever have you. He will notice. And immediately after class, he'll run to tell a teacher.
Koda: He will cry of he finds out. He's going to hug you or offer you his bunny to hold. He just wants to make sure you're ok. He'll probably try to tell a teacher but if you tell him not to he won't say anything. He'll just leave a note on the teachers desk.
Ojiro: He is going to hug you tight. He will take you to see a teacher, but he won't really drag you out force you. On the way, he'll reassure you that you'll be fine. He'll hold your hands or rub your back and stay right next to you the whole time.
Sato: He is going to bake you all kinds of sweets because a good snack can help brighten anyone's mood. He'll bring you sweets all the time for a while before he actually confronts you about the issue. When he gathers up the nerve to do so, he'll listen carefully about how you feel and offer to help however he can.
Sero: He will be a little upset. He'll wonder why you didn't confide in him. He's going to make you answer his questions like, "how long" or "why". He won't mean to sound so mean about it, he just can't wrap his head around why you would hurt yourself like that on purpose.
Shoji: Immediate hug. He won't let you go. He's going to keep holding you and try to talk to you, asking questions or just comforting you. He won't try to rush you to reply, but he will get impatient. After a while, he's going to take you to talk to a teacher.
Tokoyami: He will let his emotions take over. He's going to be all over you asking questions. He doesn't like seeing the people he cares about getting hurt and you are no exception. During the day, when it's easy to control Dark Shadow, he will stay by your side but have Dark Shadow bring you blankets and food and sweets and everything you'd need to feel comfortable. At night, he won't stop thinking about what he saw and will need to sleep with lights on just in case Dark Shadow is uncontrollable. He's always thinking of you and trying to figure out the best way to help you.
