When you get something stuck in your eye such as a eye lash or a small fly and it goes underneath your eye lid to the back or your eye, what happens to it?

It’s going to sting like hell for a while till it settles in and the tear ducts will eventually move the object toward the corner where it will come out, even if it is during sleep….
Unless it is a serious foreign object like a piece of wood ,metal shaving, etc. Then it might become a job for a professional to remove

uhg another bad question
Your eye will water and it gets flushed out.

The front surface of the eyeball is covered by a thin membrane called the conjunctiva (that’s the layer that turns red when your eyes are irritated). Just inside the eye socket, the conjunctiva separates from the eyeball, doubles back on itself, and lines the inside of the upper and lower lids. As long as the conjunctiva is intact, the inside of the eye socket is effectively sealed off from foreign objects that get in the eye.

Not a bad question at all, IMHO. It’s not at all obvious why stuff can’t slip around behind the eye

I think that most foreign objects that end up in your eye socket will work themselves out eventually. Don’t worry that your eye socket is filled with eyelashes.