Its a darned if you do and darned if you don't. If I do not help the chick and it dies its oh no I should have done something. Help the chick and it dies oh my I screwed up.
You did nothing wrong and if you keep hatching you keep learning.
SOme chicks just do not make it for 1 reason or another.
you could put alittle coconut oil (vegetable) on the membrane to keep it soft. The oil may dry after couple hours.
Not unusual to for chick to take break after pipping and start zipping 24 hours later.
You could take the egg shell off where the zipping has started very slowly and carefully if...