Oh, that looks to me like something that will come off with shedding, but which will take more than one shed to come off... my bps sometimes get abrasions that look kinda like that after rubbing their heads or sides too aggressively against their hides during shedding, and it usually takes a couple sheds to go away.

I've heard not-so-good things about using products to help shedding, though. Like, sometimes they actually make the problem worse, even in the short term? I'd just put a wet towel on top of his hide and replace it every two or three days until he sheds.

But if it doesn't look markedly better after another shed, I'd take him to a reptile vet.