Ok... warm side can go a touch higher higher. BRB's can have neurological damage if subjected to ambient temps over 85*F, but a hot spot at that temperature or even a bit higher with lower ambient is fine. As long as he can move to a cooler area he'll be ok.
After a regurgitation don't feed for three weeks and then offer a feeder a size smaller than it was taking. So, if it was eating mouse fuzzies then offer it a mouse pinky. Don't feed again for two weeks, then offer another smaller feeder if the first one stayed down. If that one stayed down then offer a regular-sized feeder two weeks later. Since he's regurgitated I wouldn't feed him more than every 10 days. Since BRB's are kept at lower temperatures they need more time to digest a meal, even my babies are on a ten day schedule, and the feeder only leaves a minimal lump. Putting them on a 5-7 day schedule like you do for a ball python gives them problems.
While you're waiting the three weeks before feeding again, go to thebeanfarm.com and get some NutriBAC, it's a reptile probiotic powder. Dust his feeder with a tiny bit of it for the next few months to help re-establish his gut flora.