that right one looks infected. i am not sure what to tell you about treating it. i dont want to give you some advice that im not 100% sure about. i would say..dont waste your time waiting for a post on a forum. try to keep him away from any dirt or anything dusty that might make it worse. if anything change the substrate to paper towel or a few towels. i hope this helps.

-----
1.0.0 arg. b/w tegu
1.1.0 white's tree frog- popeye, jack
0.1.0 southern painted turtle- ms.tortle
0.1.0 crested gecko- crimson
1.0.0 pinto hedgehog- dante