Using a heat mat (UTH) is the most widely suggested method of heating. I am no expert on bulbs and, in fact, have no first hand experience with them. If you can't get the bulb any closer to the viv (if it is already sitting on the top) then I don't know how you could get it warmer without a higher wattage. I would worry about him/her getting a burn if it can climb up near the bulb. Putting a towel or something similar over part of the top might help to hold some heat in. :shrugs: Again, UTHs, heat tape, and the like are the most commonly used heat sources.
I have a young corn that is extremely defensive and strikes constantly but she has never regurged a meal. But they are all different. Just try not to handle him/her and give 7-10 days before the next feeding which should be a very small meal (like a pinky head).