Crease under the plastron

[pinnie]

pinnie​

Hello​

I have an issue at hand.Pls look at the pics and tell me what is this discoloration of skin under its mouth? Can it be mosquito bite?..or scratches from its own shell beneath the mouth?Other thing ...those creases on plastron...is that normal?
For ref ...my Tojo is 4-5 mnths old, Indian star.

 

[Tom]

Plastron is normal. Chin color is likely staining from substrate. It does not look scratched or irritated to me.

 

[pinnie]

Tom ..u r a blessing.
Thank u for quick response.