If he's eating, defecating and shedding, a vet visit probably isn't necessary. You can bag up a poop (put in fridge) to drop off at the vets to do a fecal float just to make sure he doesn't have any internal parasites. That's about $20 for the test, and the snake doesn't have to come in. If it tests positive, medication is about $10 for 2 doses.