What are these spots on back side of tortoise?

[Shambhu]

Hi,
I have almost two years old red footed tortoise. Seems like healthy. Eating and walking and sleeping. But I noticed white spots on backside. What are these? I scratched but it is not like cotton or mold texture. Just like shell. But white patches. I have attached photos. It’s above shell is good.
Thanks in advance for your help.

 

[wellington]

It could be rubbing on something or a fungus starting
Apply athletes foot cream on it daily after a very light wash/scrub of the areas. Do this for a couple weeks. If no improvement then stop. If it starts to improve, keep doing it until gone.

 

[Shambhu]

It could be rubbing on something or a fungus starting
Apply athletes foot cream on it daily after a very light wash/scrub of the areas. Do this for a couple weeks. If no improvement then stop. If it starts to improve, keep doing it until gone.

Thank you. I will.