im 15 and i eat the skin off my palms

I am only 15 years old, and when I was 5 I burnt my hands, and then I started to pick and eat the skin off my hands. It started when I became really nervous about my burn, and I wanted it to go away.. but I have been eating my skin ever since... When I turned 10 I started picking and eating skin off my bottom of my foot. I stopped that around 13. But to this day, I am still picking and eating my palm skin! Even as I type! I do eat the skin off my lips as well but not AS BAD. I do not know how to stop, and i really want to stop and let my hands heal.