Enclosure looks nice, he has a good home. Can you post a close up of the tail when it's dry ? It might have gotten stuck under something like the cave, like a freak accident. Since he has a wound, keep Neosporin on it but don't bathe him a lot. Water can introduce mote bacteria in to the wound, although you can add betadine to the water when you soak him as long as he doesn't drink it. Raw honey is a good option as well, being a natural antibacterial. That's all you can do for now but if it gets worse , find a qualified vet to take care of it. He's beautiful BTW !