problem, 17 year old white male?

I don't think you have cancer, but you should pull the foreskin back and stretch it at least 3 times a day. soon the skin will be able to pull back like nothing. I know what you mean about being afraid of the skin going behind the head and getting stuck there. I have to pull the skin back on my 1 year old son and I get scared to pull it back too far cause I'm scared of it cutting off circulation to the head. But anyway you need to stretch the foreskin often, it is possible that aculated dirt and what not is acting like a glue and preventing your foreskin from going all the way back.