Terrapin Eyelid got stuck

by Rita
(Bandra, Mumbai, India)

1. A terrapin (i guess because we live near a creek in Mumbai - India)"Loity", walked into our lives 4 mths back. Refer photo attached.

2. Seems to be 8-9 yrs old from the lines in shell pattern.
3. Do not know if male or female - since there is no other to compare.. and few have literacy in this, Vet docs are mostly for cats , dogs.
4. Problem ? I once noticed that an eyelid did not open for 2 hrs till he soaked it under water for a while & rubbed it with his front paw.
5. Problem ? He only eats a tiny snail or two or a tiny fresh prawn once in 7-10 days.
I wish you could address all my 5 concerns to give me comfort.