I think you will be fine, about 5 days ago, I left for work in the morning but before I did I checked on the eggs and it was all good humidity 56% and 99f, anyways when I got home from work I didscovered that in the morning I didn't close the bator lid completly so when I got home the humidity was down to 16%, I thoght that I had killed my babies, I asked here in the forum what I should do and most people agreed that I should let it keep going and I did, today it's day 13 and I candled them and there still alive, so I doubt that your babies are dead, more important than humidity it's the temperature, now on that you can't afford big drops. I'm pretty sure your chicks will be fine.