URGENT: Need Advice About Ball Python Swollen Face

[GoldKingCobra]

Hello. My two years and five-month-old male ball python, Poltergeist, has a badly swollen face, which I believe three things could be responsible: RI infection, damage from rubbing/pushing his enclosure or allergic reaction to a painted castle thing designed for fish.

For the RI, there is no discharge coming from his mouth but there is a slight "whistle" noise when he breathes. He has stopped eating ever since the swelling occurred, which beforehand, he ate anything I gave him. Another reason why I suspect it to be possible RI is because his humidity may have spiked too high sometimes, as I read it at 80% occasionally (though, it is usually 65-70%). Also, there was another thread I read somewhere on the internet that sometimes RI, in rare cases, causes swelling...
For the rubbing/pushing cause, I heard him at night trying to get out of his plastic bin enclosure that measures roughly 32x14x14 inches. Also, the plastic from the air holes sticks inward in the enclosure, which he could have injured himself on (I'm currently trying to get them removed). What makes me uncertain about his face being injured is that there is no apparent injury, puss or anything inside his mouth or outside. The only issue is that his face looks grossly distorted, and he refuses to eat.
For the castle, the swelling occurred just around the time I installed the castle for him to climb on. He could be having an allergic reaction to it but I removed him from his enclosure and into the "hospital" bin. He's been there for a couple of days now and there was no change in his swelling when I did this. In fact, it seemed to have gotten worse.

Treatment I've tried: I moved him to my small "hospital" tub and amped the hot spot to 95 degrees Fahrenheit, removed any water (bowl and spraying) to try and see if the moisture from his face will go away (I heard that this was tried on that thread about the rare RI but the results were not there). His swelling has slightly gone down but I could just be seeing things. I have also given him vitamins to boost his immune system (a liquid for reptiles containing glycerin, deionized water, vitamin A palmitate, niacinamide, riboflavin, cholecalciferol, ascorbic acid, thiamine hydrochloride and pyridoxine hydrochloride). It says it has vitamins A, D3, B1, B2, B6 and C in it.

Enclosure: A springtail bioactive with false bottom, coconut chip bedding with bioactive dirt with charcoal, two of the same plastic hides, one castle hide in the middle for him to climb on, roughly 30x14x14 inches plastic tub, hot spot 87-90 degrees Fahrenheit, ambient 70's-80's degrees Fahrenheit, heat mat with thermostat. I was having trouble getting the heat mat the correct temperature for a little while, because the plastic is thick and I didn't want to burn him, so it might have been too cold for a couple of days but I don't remember. I have a heat gun, btw.

Temperament: Besides refusing to eat, he acts normal. He is active and moves around when out. If I let him on the floor, he explores like he usually does unless he's "balling-up." I haven't been holding him ever since I noticed the swelling. Normally, I leave him alone and only hold him once or twice a week. I occasionally take him outside to explore.

I would greatly appreciate it if someone could give me advice. I am willing to go to a vet but it's expensive and I don't see how the vet could help (if they could, please tell me how). I don't want to spend money for nothing, as I'm borderline broke, but I'm more than willing if that's the only thing that can be done.

What do you think is going on and what should I do? Thank you.