Help For Severe Dermatophagia

I'm 15 and have ad dermatophagia for as long as I can remember. It started off with just picking off tiny pieces of skin and eating them but over the years, it is becoming worse and worse. I now find myself chewing my skin several times a day until my fingers are painful and bleed, my fingers (and thumbs in particular) are scarred dark red and the skin is rough and swollen. Its actually getting embarrassing now, I was sitting on a bus and the person next to be asked why my fingers were so red, with this in mind, I'm worried it will affect my future employments. I've tried that foul tasting varnish- putting it all over my fingers, and it doesn't make a difference, I just ignore the taste and chew! This is a habit i just cant get rid of, its painful, ugly and embarrassing, how can I stop!?