Your heating pad needs a thermostat to regulate it. What are you using to measure temperatures/humidity?
Don't waste your money on the thermostats sold in pet stores. They are unreliable at best. Here are 2 good ones.
Budget: http://www.amazon.com/gp/aw/d/B000NZ..._bxgy_ol_img_b
Best choice: http://spyderrobotics.com/
The hot side needs to be between 88-92 degrees, the cool side needs to be between 78-82 degrees. No part of the cage should ever get above 95 or below 75