Is this shell rot?

[Patjava30]

I rescued this little guy a few weeks ago, he wasn't being cared for properly. I noticed this morning that he has a spot on the underside of his shell. It looks like it may be healing. I've read a lot on proper care and have been doing a good job following those guidelines. Any help would be great

 

[Yvonne G]

What I see on that plastron all looks like normal wear and tear.

 

[Patjava30]

Ok, what about the little "hole" by his leg?

 

[Yvonne G]

Some sort of old injury.

 

[Patjava30]

Thank you!!