Keep him warm at least 80 degrees and I would stop using a uvb bulb altogether and just use a heat lamp until he is better. When I have read about problems like this the fastest recovery times have been a week I believe but some take longer. You should try soaking him more than once each day 30 minutes+ if you can (maybe even adding pedialyte flavorless to soaks), this helped a lot with one of my torts. Sorry I don't have more advice I only had to deal with a sick baby tort once so far. Also try to stay calm and relaxed I know how stressful it can be.