Hey, I hope your frog is still okay, but that looks serious. I guess a vet isn't possible? Sorry for the late reply.

Whatever happens, it's going to be important to make sure the material from the tank is sterilized thoroughly. Make sure not to just dump the substrate in your back yard. Reg leg is not something you want to pass on to local frogs. (It may be something else entirely, but I suggest not taking chances.)

Once again, I'm sorry.