Ok so some of my tortoise have shells that they have scratch off, to the bone. I was on vacation for 2 weeks and I had a friend watch my sulcatas, he didnt watch them... when I came home I found that they had dug a 12 foot deep hole under my cement pool deck. Let me clarify the roof of the hole was a spiky cement slab. When I got all the tortoise out I noticed that there shell was scratched to oblivion. I can see there bone of there shell.will the keratin of there shell ever grow back???