If your guitar has a truss rod cover behind the nut, try shimming the cover up a little. This will raise the cover and close that gap up and thus prevent the wedgie from falling out. Get some slightly longer screws at the hardware store or your guitar spare parts box (tackle box) and place a smaller section of a used, worn truss rod cover between the screw wholes. Cut to size and fasten down. An old plastic library card or wifeys credit card will work as well. You can cut these to size a lot easier then an old truss rod cover. An FYI from Fingers That Sing!!