I'd tip it over if possible so that it's lying on its side, pip pointing up. Sometimes they can hatch all by themselves. I've never come across this myself so I'm not much good for advice. Do a search for 'chick pipped at wrong end' and see what advice you an find.
Having gone through the last 48 hours with NINE out of fourteen eggs pipped at the wrong end, I would say the first thing you need to do is BE CALM. I lost one but eight are running round their brooder as we speak, happy, healthy and vigorous!
I agree, it might be a good idea to tip the egg so it has better freedom to zip round the egg when the time comes. If you can see beak, the chick can breathe and that's the important bit. If it has pipped straight through the egg at the wrong end, it is also anything up to 24 hours ahead of the game. The chick would normally pip into the air cell first, then have 12 to 24 hours to rest, gain its strength, learn how to use those lungs, before it pipped through the shell. Your wee chap has done that in one hit so you need to allow 24 hours for it to get to the usual external pip stage, then up to another 24 hours before it would start the zipping, THEN if it is having problems, you can consider helping it out.....read the 'step by step assisted hatch' thread on here, it is worth its weight in gold!
I can tell you that one of my nine did, in fact, get out with absolutely no help from me at all, so it is perfectly possible. The other eight needed varying degrees of help...mostly just making sure that the membrane was clear of the pip hole and did not dry up during the much longer period before zipping started.
If I could could give you any advice, based on the two fully assisted hatches I have performed today, it would be to take it SLOW!! Do a tiny bit at a time and give the chick plenty of time, in between, to rest and to potentially get the rest of the way out on its own. If you see blood, STOP, give it an hour or so and try again, slowly! Check as you go to see if there are active blood vessels and check down to the rear end of the chick to ensure the yolk is absorbed before you release its head in any way. Once you release the pressure on their head/neck, they will kick out EVEN IF the yolk is not fully absorbed and then you have a world of problems on your hand.
If you do it properly, you can have really positive results but rushing the job will likely lead to a dead chick so take it easy xxx