Not possible. It can get stuck way up under your lids, but never behind your eyeball. There is a membrane (called your conjunctiva) that prevents that. More than likely, you'd know if the lens was still in there, so it may have popped out. If your eye turns red, tears up a lot, or you start to get some headaches, you may want to go see your optometrist and see if the lens is stuck up under your upper lid.

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