Quote Originally Posted by dr del View Post
Looks like he rubbed it pretty badly - probably on something in the enclosure.

It is a very hard thing to resist taking the snakes out of less than perfect keeping conditions but my doing so you are just rewarding the shops poor care and allowing them to do it to the next set of snakes they buy in.

There is no realy good answer to the problem I'm afraid.
This is why I support breeders (and hope to do some breeding of my own in the future). I think PetCo feeds live mice/rats and that hole on his head looks like it might be a bite/scratch from a live mouse/rat. That or like you said, he scratched himself on something in the enclosure...although, there isn't much in the way of hides in that enclosure.