I thought the same thing on the 15th then 16th came still no other baby. It may take up to 3-4+ for the other baby to hatch. Mine hatched one the 15th or this month and the other one hatched on the 18th on this month. That about a 3 day difference . I hope this helps if it looks good leave it . It will hatch or wont wait it out. Good Luck and i hope it hatches soon for ya
They should hatch within a few days of each other.
When were the eggs laid and what temperature were they incubated at?
This will give us an idea of when the eggs should hatch. As long as the first egg didn't hatch early, then you MAY be able to open the second egg without causing harm. But I would give the second egg up to a week to haych by itself.
The temp pump is going to make it difficult to estimate incubation time. Also temperature fluctuations have been known to cause birth defects. I lost all but 2 eggs last year because I jumped the temps like you did. Hopefully your geckos come out fine.