are you positive its a regurge and not a mouse that was left by the animal not eating?
if you are positive that its a regurge. Leave the animal alone, give it normal care/water for at LEAST two weeks. Dont try to feed the snake.
In the mean time, if the animal poops, collect it and bring it to the vet to get a fecal done, to make sure there are no parasites or other issues you may not be able to see. ( They usually are around 15-30 bucks, sometimes more depending on your vet.
After the two weeks, you can try feeding a smaller prey item than is normal. See if the animal kept the prey down, and wait. if they did, you can try offering normal sized prey the next time you feed. again, one prey item, and just wait.
In the meantime, make sure your temps on both the hot and cool side are right, and get a fecal if you can to the vet for examination.
If the snake regurges AGAIN. Bring it to a vet. Immediately.