I don't think I'm the best person to answer this, but that seems a bit too warm. The Husbandry FAQ says 75-80 and 80-85, so you've got a warm side and a warmer side.
It also suggests you not let the temps get higher than 90, and you're getting kind of close so be careful.
However, I don't know any way to cool the viv down, aside from turning up the AC.
I'd suggest making sure the viv isn't sitting in direct sunlight, and that your snake always has fresh cool water.