This is my first reptile. He is a bearded dragon about 6 months old. I noticed shortly after we got him that he had a small scab on the top of his forearm. Since then it has gotten worse and has spread to the underside of his arm and more recently to his pinky finger. The finger is black and looks like it's going to fall off. He is still eating but he is not using that arm at all. I have been soaking him in a diluted iodine solution and trying to get the dead skin from around the area. I have also tried chlorahexadine and topical antibiotics but only for a day or two. Any suggestions are appreciated