Just be CERTAIN that the membrane covering the beak/nose has a hole in it so air can get in. The biddie is probably sleeping. Pick it up and talk to it -- see if it responds. I picked a few of mine out of the shell, CAREFULLY, and they are fine so far (day 5 after hatch). They weren't making any progress, and thought I might lose them. Just stop if there is any blood! you can make the hole a tad larger, but be careful of the blood vessels in the inner membrane. Hope it helps.
When I went to investigate the non-hatchers on day 23, I broke into the air sac part of the eggs of the non-hatchers. Unexpectedly, I had one that was still moving under the membrane - not even close to pip... hardly had an eggtooth... and with the big end of the eggshell off! So I poked a hole in the membrane right by the beak, and covered the exposed end of the egg from the "breathing hole" down with a small piece of wet paper towel for a patch. It kept drying out, so I put the other corner of the little paper patch hanging in a little bottle lid in the incubator.
Well the next morning it was still alive. Left it longer... and in the afternoon I picked it out of the shell. Its head was swollen up a bit, but I put it on a dry paper towel in a plastic box in the brooder... thought it was a gone-r for sure. It kept breathing, dried off, lifted its head now & then... not too encouraging, but not gone yet....
Eventually... I'll be darned if the thing isn't running around just like its hatch-mates now a couple days later! It may not make it, but darn it, they can sturdier than we think sometimes -- (NOT a recommended course of action... but if you're discarding the left-over, it turned out a whole lot better than I would have imagined)