That bulge is disconcerting. I’m very new to snakes in general but my understanding is a slight bulge after feeding for Boa’s. After a poop there is a bulge like that, somethings going on. Like Sauzo said, a good sook. I know a friend of mine has done that with an Iguana and helped it poop. The vet is really making sense though. Shame on that breeder for passing on an ill animal if that is the case. I hope everything works out, not a great way to start out.