Do not feed him for a minimum of two weeks.
In the meantime, their is a product called Benebac which most major pet stores sell in the bird section. It is a probiotic for both birds and reptiles. I would begin dosing his water with it. When you feed him again, add a light sprinkle to the prey item.
Benebac does a good job in replenishing the beneficial bacteria in the snake's digestive system that can become compromised in a regurge event.