BLUE TONGUE SKINKS

I just got a bts and he has what it looks like kind of a scab in the side of his mouth (it looks dry). I was told by the seller that it is stuck shed (cause he’s shedding) but now taking a closer look I don’t think that’s what it is... can this be mouth rot? or something else? Do I have to worry? It seems like it doesn’t continue inside his mouth…
Thanks!

Hi there, it doesn't look like it is mouth rot. Looks more dirty and just needs to be cleaned.

Exactly. They often have food and whatnot stuck around their mouths.