Shell Rot on Hinge-back Tortoise

[Yurtle]

I’ve started to notice my Hinge-back Tortoise getting some white growth on the gaps between his scutes. Is this shell rot? Or are his scutes just scraped from wedging himself between rocks in his enclosure? It’s only on the carapace of of his shell and not on the plastron anywhere.

 

[wellington]

Looks like growth too me nothing else. Just getting some lighter color in?

 

[SweetGreekTorts]

That looks like marbling to me. Like Wellington said, it's new growth that is lighter in color. Some species develop marbling in their coloring as they grow.