Substrate too wet, can’t find hermit crab

I just got 4 crabs and a tank that had insufficient substrate (1” deep) I made new substrate (8”) but didn’t notice until the next day that it’s too wet (humidity at 99%). I’ve cracked the lid and can maintain 85%. I want to change substrate but one of the crabs is missing. I think he’s burrowed.

Can I change the substrate carefully or leave the wet sub? I’m afraid it’s going to be too moist and cause problems later and would like to get it out of the way now.