Will caring a LOT help a friend who self-harms at all?

Oh god, yes, it'll help a thousand times over. I know exactly how he feels. I do that, and when my sister found out she yelled at me about how stupid I was. It made me feel so much worse. If someone had been there for me like you were for him, everything would have been so much better. So I can promise you that you helped him a lot and possibly saved his life. When he thinks about cutting, he probably sees his face and stops because you care about him. Good job!