a cat I am fostering has a ragged edge to one of his 3rd eyelids. i don't know how long it's been like this since it doesn't protrude most of the time. it doesn't seem to bug him, his eyes are clear and bright and his behavior is frisky, but it definitely looks like the edge is a bit jagged, i can't tell if it's from an injury or if it's something else. anyone ever heard of this before?