it might be really hard for you to do but try and see a dr. self harm is something i have struggle with for a long time and i find it difficult to talk to my friends and family about it because of the negative associations/ taboos associated with it. Like you people dont know im upset, its something that i bottle up, but as i am gradually learning, talking helps and asking people for support isnt a bad thing! If youre worried about how people will react go see a GP. They will talk things through with you from a more informed point of view nd talk about steps you can take to help your current situation. They wont tell anyone, and they wont judge you.
Good luck, OP.