3rd eyelid question.

okay.. can someone tell me if the only time a cats 3rd eyelid comes out is when they dont feel good.

Lilos will come out but then the next day not be out. Also the kittens have just been treated for worms and ever since I started the first day of it I noticed that theirs are out.

I've noticed with my cats that when they're extremely relaxed and contented, such as during a session of cat massage, the third eyelid is often partially extended. I've never seen it just come out for no reason, though, which is what it seems you're describing with Lilo. Can't comment on the kittens, though.