I'm so sorry, but you've done what you could for this snake, & I'm really glad that you talked to the guy you got him from- I hope he comes through with the refund. It might be he really needed the money- but yes, it was dishonest. I doubt he's able to eat or that the "wound care" will matter, but it's easy enough if you have some Betadine on hand. You never know?
I agree that from your description, this snake isn't likely to survive. The guy you got him from actually bred this snake? or was he just "flipping" (re-selling) him? Is this the only sick snake he has? NOT that you can believe much of anything he says now- so while I'd love to believe this snake was merely overheated, I also have to say that it's potentially IBD, & if I were you (thinking about another pet) I'd assume the worst & clean as if that's what it was. The only way to confirm it would be expensive testing & you'd need to see a vet, so I doubt that's in your plans.
It's been a while since we discussed IBD on here & I've never dealt with it- there might be some newer info now- I'll get back to you or you can do some searching also, but it used to be recommended to wait months (6?) or even a year (I think?) to be sure your home is safe for a new healthy snake. Unfortunately, BPs are like the "canary in the coal mine"- they succumb rather quickly to this nasty disease. (Some boas or other snakes can carry it for a while without symptoms- maybe even share it without ever getting sick too?)
It's really hard to see a helpless creature in this kind of shape- I must say, you seem to be handling this quite well.![]()