the heat pad could be - 1. Too small, 2. Defective, 3. not regulated properly.
You could try a different heat pad, make sure you have a reliable thermostat. Make sure you measure the temperature inside his hide box, and not just randomly in the cage somewhere. If possible, aim a Infrared Temperature Gun directly at the heat pad and see what it reads. Most of those pads unregulated can produce heat of around 115 degrees F, and that is why a thermostat should be used. Some pads get even hotter than that.
As far as the humidity, keep in mind the more a cage is enclosed, the higher the humidity will be. You could allow more air transfer throughout the cage and that will lower it a bit. On the other hand, if you live in an inherently humid area, you might not be able to do much about it. Make sure there is no spilled water or dampness inside the cage. Obviously, if you can get the heat up to where it should be, that will also help to lower the humidity a bit.
70% humidity is not bad once in a while. But it would be nice to have it around 35% to 50%.