Help with shell question

[Rennea]

I got a male ornate adult box turtle a couple of months ago. I have him in a 120 gallon terrarium for inside with a uvb and a ceramic heater. At first his shell was good a little damage on the bottom but top was perfect but now his shell edge is almost colorless not sure if this in normal or if I should take him to vet. Any help would be great. Thanks

 

[Yvonne G]

That is chew marks. Is the turtle housed outside? I would say mice or rats are chewing on the edges of the shell.

 

[Rennea]

I have outside pen that he gets to go out to sometimes with my redfoot tortoise, but he is only in there a couple of hours during day. Will it heal on its on?