Stuck shed???

[Armiyana]

i missed the updates on this one. I'm sorry.

that definitely is a strange injury of some kind and not just shed skin. The snake does also seem someone dehydrated/thin/both from the way the skin fold is showing along the side.

FIND A NEW VET. If that is what they told you, they don't sound qualified to be working with ball pythons.
You should definitely try to get this animal tested for some sort of parasite or bacterial condition.
I would do a soak with just regular water for a few minutes. that will give them a chance to drink. After that you can add some iodine in to help flush the wound. if you are able to find some silver sulfadiazine use that on the sore, just gently wipe it clean before the soaks. If you can't find that, you can use neosporin without painkillers, but be sure to use a very thin layer only on the wound. It can affect the still healthy scales.

Double check your temps and any materials he could injure himself on in the habitat.
They can definitely start eating again after a long hunger strike...but you need to find out why the snake's skin is peeling this way (almost similar to snakes I've seen with severe malnutrition or vitamin issue, but not quite) and get them started on a path to recovery.
You may also need to consider a short intervention with tube feeding.

EDIT: somehow my page also was not properly updated and did not show the last couple of updates today as well. Ugh. I should remember to always hit the F5 key XD;
You still have a small window to make things right. It can be hard. But this new vet sounds like they have a much better head on their shoulders.
I recently lost a snake to a sudden infection like this. They hide it really well. I hope that things for yours gets better.