Please get him to ANY VET immediately, please don't hesitate or wait at all, he's been suffering greatly for a long time, and he's going to die without immediate antibiotic intervention, by both injection and oral meds. The infection has already spread throughout his mouth, jaw, throat, upper respiratory system, possibly into his lungs, and next is going to be his eyes (blindness), his ears (deafness), and his brain (death), as it's too close and been present too long in his head. He'll most likely become septic and die first, which is a very painful, agonizing way to die. When a simple vet visit for a culture and sensitivity test, an antibiotic injection, and a round of oral antibiotics plus some nutritional supplement like Oxbow Critical Care paste is all he needs, a general vet can certainly do this. They can get a bacterial or fungal infection from anything, just like we do, who knows where, but I'd get him off sand IMMEDIATELY too, as it both harbors and spreads bacteria and fungi, and if he's still on sand and he's this sick, no matter how often you change his sand, it's going to continually reinfect him, possibly spread the microbes to his skin and elsewhere, plus he certainly doesn't need an impaction on top of this infection. Dump the sand, completely disinfect the entire enclosure inside and out, as well as everything in it with either bleach or F10 disinfectant, and put down clean, dry papertowels that can be thrown out as they get soiled. And keep using the papertowels as his substrate throughout his medical treatment to deter bacterial growth inside his enclosure. And please, make a phone call to your nearest vet now, doesn't matter what kind of vet, the concept of doing cultures and prescribing the corresponding antibiotics or antifungals is something they can all handle...And also please consider this, any vet can also GIVE HIM SOME PROPER PAIN MEDS AND ANTIINFLAMMATORIES!!! HE NEEDS PAIN RELIEF IMMEDIATELY, HE'S SUFFERED FAR TOO LONG!