Usually when someone asks, "Can contacts get lost in your eye?" they are wondering if it's possible for a contact lens to become dislodged from the front of the eye and get lost or trapped behind the eye. That can't happen.
The inner surface of the eyelids has a thin, moist lining called the conjunctiva. The continuous nature of the conjunctiva from the eyelids to the eyeball makes it impossible for anything to get behind the eye and become trapped there.
Sometimes, if you rub your eyes or get bumped in the eye when wearing a soft contact lens, the lens might fold in half and dislodge from the cornea. The folded lens might get stuck under your upper eyelid so that it seems to have disappeared.
If this occurs, you can usually find the lens by adding a few contact lens rewetting drops or artificial tears to your eye and then gently massaging your eyelid with your eye closed. In most cases, the folded lens will move to a position on your eye where you can see it and remove it.
If you can't find your "lost" lens with this technique, try to gently turn your upper eyelid inside out. (It's really not as gross as it sounds.)
The best way to do this is to place a Q-Tip horizontally over the outside of your lid. Then, while looking down, grab hold of your eyelashes, gently pull the lid down and quickly evert (flip inside out) the lid by folding it over the Q-Tip.
Keep looking down and tilt your head back. With your other eye open, you should be able to see the folded lens. Gently move the contact lens with your everted eyelid until it moves onto your eye so you can remove it.
If you cannot remove the lens from your eye with either of these methods, it's time to call your eye doctor. (Please do not fish around for hours with long fingernails pinching your eye to try to find the lens if you don't see it.)