Hello! I posted some photos of the underside of our 1-year-old Greek tortoise, and doing so noted some dark brown/black discoloration and softness on the underside of the shell. I have read a few posts about shell rot, but this is either a really bad case or something else. The shell is as clean as possible in the picture - the discoloration is IN the shell, not on the shell. I have read about using Betadine on the affected portion but am still not clear how to apply, how often to apply, or how long to apply the Betadine, or if there is something else to do entirely. This problem was already starting over 7 months ago when we took the tortoise to the vet for a check-up, and the vet didn't say anything about it. Please help!!