Get it checked out right away. It could be skin cancer. I have skin cancer on my shoulder, a little smaller than a dime. Doc is taking it off next Friday. Mine started out small, like the head of a pin. It itched, and when I scratched it, it bled and never healed up. Got bigger and I thought it was a boil but after two weeks of heat treatments and tea tree oil it did not get better so went to the doc and had a biopsy. Doc said I should be okay after he takes it off. No chemo or radiation. So, go get yours checkout, okay.