If it hasn't zipped in 24 hours, you may need to assist. I as a matter of fact just assisted an egg yesterday that was upside down and pipped through the top of the egg. It didn't have enough room to move around and zip. It came out finally. Unfortunately it died because it was too weak. If 24 hours passes, assist. Read this-
https://www.backyardchickens.com/a/step-by-step-guide-to-assisted-hatching
https://www.backyardchickens.com/a/step-by-step-guide-to-assisted-hatching