hands

i started to rub the knuckles until my skin blistered then i pick at the blisters till sore, then scab over and i pick all over again till i bleed and now i have 5 horrible marks on my left hand but i cannot help it. i put plasters on i have 5 on now. i also do the same to my elbows. and sometimes i even bite the inside of my mouth. this is not right is it?