That happens more often than you'd think. There are different things that can cause them top be early, my chicken eggs regularly hatch a day or even two early, whether in an incubator or under a broody hen. A normal cause is that the incubator is running a tad warm, you might want to check that before your next hatch. But it could be other things.
There is a big difference in what might happen and what absolutely will happen. That might have caused problems but often it does not. I've done that with chicken eggs before and they hatched fine. So try to relax, you have done what you can for now. And it was the right thing to do.
Sometimes if the egg dries out too much the membrane around the chick, or on your case the duckling, can shrink around the baby so tightly that it can't move to hatch. Sometimes, not always. Since the duckling has pipped it can breathe. Sometimes after pip the duckling can zip and be out of there in an hour, sometimes it takes 24 hours or maybe even more. If you have a slow one that will really worry you. I know, I've been there.
You have removed the turner and raised the humidity. Don't do anything else right now. If you try to "help" you are likely to cause a lot of damage. The duckling has to continue to get ready to hatch. If you start breaking it out before it is ready you can kill it. It needs to absorb the yolk and dry up some blood vessels that are outside it's body plus do some other things.
My suggestion is to do nothing more until tomorrow morning. Give them time to hatch on their own. But keep an eye on the ones that have pipped. If they are shrink-wrapped you will probably see that membrane around the pip turn white as it dries out. There are a several threads on here about helping a chick plus I think there is something in the learning center at the top under articles. Use the time to read those so you are ready.
There is a chance you can dry out some others if you open the incubator to take one out to help. That risk is pretty low but it is possible. You have to weigh the risk of causing other eggs problems versus that one specific egg. I don't just randomly open the incubator during lockdown but if I have an emergency inside I will. I just pop that egg out and re-close the incubator. I don't do it but if you want you can mist the insides with warm (not hot) water.
I won't lie to you, it is possible one of those eggs could have problems. But the likelihood of problems is pretty low. Even if there are problems there are ways to deal with them. Hard as it is the worst thing you could do right now is panic and try to help. You meed to force yourself to wait and prepare yourself in case there are problems.
Good luck and let us know how it goes.
