As they say, "buyer beware".His lower jaw is swollen, but I agree that it's best to let the vet check it all out...& since you're planning to keep him, I hope he makes a
full & quick recovery. None of this means that he doesn't have mites too, btw...so pay close attention & if you see any tiny (pin point) moving specks (red/brown or black)
on the snake, in his water bowl or anywhere in his cage, be ready to clear out that lovely set-up, because mites hide eggs in all porous materials. I HOPE he didn't bring
home any such "guests", but this is not an ethical source, so you certainly can't rule it out or let down your guard. If you see him soaking in his water bowl, that's some-
thing that many snakes do that have mites...it helps them to relieve the itch (we presume) & some may even drown (but most mites "need our help" to drown).
I hope you find a better exotic pet store next time...many stores cannot be trusted, they're all about making money & are all too happy to sell unhealthy animals to un-
suspecting customers.