Questions??

My boyfriend is the picker...We met about 2 years ago and he slowly started to reveal his problem, then he got me into picking at his body and now its the only thing he wants me to do! At first I thought it was just something he wanted to do every once in a while, but now it has overtaken our whole relationship!!! My wake up call was when he had his head on my lap and I was taking a bit of a break from the tweezers and was rubbing his hair affectionaly and he got really angry and said "if I wanted you to rub my head I would tell you!!!!" and he handed the tweezers back to me. What can I do to help him....or me!!!!