Here are my honest thoughts: Are you using a tank? If so, try following these instructions to achieve a solid set-up for your BP. (Hint: Covering the lid of your tank with tin foil will really help lock in humidity and heat!) You don't mention your substrate, but cypress and cocohusk tend to hold humidity the best.

Your analog thermometer is not reading the hot spot, only the air around the hot spot. The actual hot spot itself (ie. the surface where your BP's skin is touching) may be much hotter! Do you know the actual temperature of the surface where your BP is sitting? If not, try a cheap digital thermometer or inexpensive infrared thermometer to get a better idea of what temps your snake is experiencing.

Once you get that accurate thermometer, you'll probably realize the need for a thermostat. What's keeping your UTH from getting too hot? Right now, nothing! It could be 115 on the surface of your tank and you wouldn't know. A good thermostat is only $35... you can afford a one-time payment of $35, right?

A heat lamp can be controlled by a lamp dimmer (easy to pick up at a hardware store), which will help you adjust it year-round. Just turn it up or down as needed to keep the lamp at the right temperature.

Good husbandry doesn't have to be expensive and is worth the money. Personally it doesn't matter if you work at Ralph's or are a student, you can and should invest a simple $50 for a thermostat and reliable thermometer. Consider it a holiday gift to your snake!