i kno not many people wanna hear this but i would get him to the vet as soon as possible...you could try soaking him but it sounds like he has some sort of infection...out of curiosity do u know if hes captive bred and born or is he wild caught/imported/farmed? that can and will make a huge difference in his health as well
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1.0.0 Frilled Dragon - Frank
0.0.1 Rhinoceros Iguana - Mo
2.1.1 Bearded Dragons - Magellan, Galileo, Lizzy, & Machiavelli