Sadly I've Been Using Cocaine For About Two Months And

Sadly I've been using cocaine for about two months and mysteriously scabs have formed on my scalp. They're extremely painful and I'm really curious as to how they appeared out of nowhere. I didn't pick, and I haven't started using any new shampoo, hair products, or brush or anything. I would go to the ER ( I don't have a PCP atm), but the way they treat me because I am an addict really hurts. The only way I'd go back to a hospital would have to be unconscious in an ambulance or something. Do you have any idea what could be the cause ???