I agree with Amy here on the humidity. Is your temp gauge inside the tank and if so check to see if its working correctly.

Burrowing for the Whites is usually that they are either trying to coll down or the moisture in the air is not enough and they are drying out.
Also, is there enough places for them to climb and hide?
Mine sleep in the Bromeliads and snake plants since they are usually damp ot wet from misting.