IMO, I would probably make a few cracks in the shell around where it is pipping and put it back in. I would take a paper towel and wet it with warm water to hold around the egg to keep it moist while I worked with it. Just pry away some of the shell. If there is no blood, I would probably removed most of the shell. If there is blood, just loosen some of the shell around the head and make sure it isn't shrunk wrapped. If it is, pull it away from the face. I did this to those 5 babies the broody abandoned while they were pipping and they did well. Good luck.