Q: While changing the valve cover gasket, a piece of the gasket broke and fell down into a hole, what do I do

Hello. I would first try to us some long mechanical fingers to see if you can reach and remove the piece. If not, then see if the hole goes all the way into the oil pan. If it does, then remove oil drain plug and let the oil drain into a pan to see if piece comes out. You may have to spray some brake cleaner down the hole to try and wash it out the oil drain. If you still cannot get it out, then it will most likely get caught in the oil pickup screen. As long as it was a pretty small piece, it should not cause a problem.