Found bullfrog with badly injured back leg, missing skin, HELP?

[herpdoc]

I'm no vet but these ulcerations look awfully like what you see with ranavirus infection and in fact you can see some areas developing on the back. I don't think you should release her (it's a female bullfrog). Bullfrogs are known to be carriers of ranavirus and generally tolerate it better than other species (like woodfrogs).