i have her in a 5 gallon tank with 4 inches of forest bed i dont know about the humidity i mist her 3 times a day i have a heat lamp with a 60 watt bulb on one side of the tank and of course a water dish and a hiding place.
Misting does almost zilch for maintaining humidity. You should probably put some water in the bottom of the enclosure and restrict ventelation. They need it humid -- even more humid than emps.
The rest of your setup sounds okay. Only one hide? You need to provide an environment in which they can hide/burrow in multiple locations. Ultimatley, they will just pick one location -- but until you have figured out how to think like a scorpion, your guess is as good as mine as to where they will chose.
Other than that, you should leave it alone for a week or so to let it acclimatize to its new environment. You should then offer some prey items.