A few days ago I noticed that my milk frog has what looked like a slightly swollen area on his lower back. I checked him yesterday and the bump had gotten considerably bigger and today it has turned dark blue in color. I am wondering if someone could give me an idea of what is going on. I have scoured the web trying to find out something but I have not been successful. I know I should take him to the vet but for several reasons I am not. I feel that it is a blister or something and maybe it should be punctured and drained because it sees to be full of fluid. He doesn't seem to mind me touching it.He is in a 280gal tank with a waterfall and a misting system. He is housed with 3 green anoles, a copes tree frog, a painted chabby, several normal green trees, and a vietnamese blue tree frog.