Please help. I don' t know what to do.?

I used to self harm. I have been free of it for 2 months. But anyway, My closest friend has been making alot of emo jokes lately. i.e I slipped and cut my arm on a rock and he something like, If I didn't just see you do that I would think you were emo. And wow, I didn't know you were emo!. It makes me angry every time he does it. He doesn't know that I used to actually do it and I don't want to tell him so what should I do?