I really need some knowledgable help on this and the sooner the better. I have a firebelly newt. recently it appeared that he had wounded one of his legs - a finger looked to be missing. Now the skin on that leg is turning white and red and the leg looks to be rotting away. He won't leave his rock and he looks just miserable. What is this? What can I do to help him? Will his limb grow back?