luckyandsammy
Teenage Guinea Pig
If is it not a developing ulceration from a scratch or something stuck under the eye lid, then it could be most likely osseous choristoma (tissue being replaced by bone). There is nothing you can do about that. It is not painful and not all that uncommon.
Links - Eye Conditions - Guinea Lynx Records
Thank you, it looks exactly like that!
Do you know if it gets bigger?
Wouldn't it irritate his eyelids? (Sorry if that sounds stupid)