It's nice to know I'm not alone

Ever since I was little, ever since I can remember I've always chewed my knuckles to the point of bleeding and to the point where the skin is absolutely destroyed. I'm 16 and I've been doing this all my life and I always just thought that I was messed up and weird and that it was just a harmful habit. I feel so glad to know that it's an actual disorder and that others share my extreme pain. All my family knows and I've told a few close friends. Everyone tries to get me to stop but I can't, I just can't. I've put bad tasting things on my knuckles and I tear the skin apart with my teeth anyway, I've put bandaids on and I tear them off to pick, I've duct taped my whole hand and still I'll rip it all off to bite my knuckles. Sometimes I tell myself to stop and that's only on days where I think I'm worth it. Other days I don't try to stop and that's on days where I hate myself. I often wonder if I have a split personality because some days I love myself and other days I hate myself, can anyone tell me if that has a name too? Or am I just really messed up? Thanks for listening to my story. I hope this can be fixed now that I know what it is.