I'm going to guess that the regurge was due to the stress of being soaked after eating recently. Unless you're dealing with a truly dehydrated snake, soaking isn't needed.
Since he did regurge you will need to wait three weeks before feeding again, and then offer prey half the size of what he normally eats. Get some reptile probiotic, either the BeneBac or NutriBAC powder. I like to dust a pinch on a wet f/t feeder to ensure the snake ingests it.
Once your snake eats don't fool with him other than to check his water and clean up any messes he may make. Offer another half-size feeder in two weeks and then leave him alone.
If all goes well you can build him back up slowly to his regular feeding schedule.