Okay. For now I would turn off the UTH. Too high will most likely be more detrimental to his health than a bit too low. 100 watt should be sufficient to keep the temps up in his tank.
Increase the temps in your home to at very least 72, if not 75, during the day and 70 at night to assist with the ambient temps in your tank. Everyone may be too warm for awhile but it will help your snake a ton.
Mist the tank twice a day and cover the cool side with a damp towel to increase the humidity inside the tank.