Day 49 Question

Hi, it is day 49 in my incubation time and i have a question. I have been incubating at 89 degrees and all of my eggs are good except for one. I candled this egg and even though they are this far into their incubation time, when i candle his egg, only half of it is dark, like where the snake is. Why is this? Should i still cut his/her egg when i cut the others or wait for him/her to pip himself? The egg is still dimpling like all of the others, and when i candle it it appears to have completely normal and healthy eggs.

Also when i candle the others their egg is pretty much all dark

I'd wait 3 days after the others start pipping (because he's a 49 and they're at 52, right?). But that's just me. As for him being tiny in there, there could have been an issue, or he could just be very small, you will have to wait and see.