Depression/body issues

I don't know why but every time I see someone better looking than me I always compare myself. It seems like there's just something in my brain that goes off an announced that this person is better than me. I'm trying to improve myself by working out and eating good but I just can't shake my worries. I used to self harm and now that I have these feelings again, it's very difficult to ignore that I do want to hurt myself. It's always on my mind. Any advice?