Well the way to adequately feed your snake is by estimating the widest part of the snakes girth at the belly region and select an appropriate sized prey. One that would leave a small bulge and that's all. Depending g on the age and weight of the snake sometimes there is a calculation of 10 -15 % of the snakes weight as being an appropriate sized meal. Never over feed your snake or give it oversized prey bc it can certainly lead to a regurgitation. Which is what this sounds like. What type of enclosure is he in and what are the temps inside? Hot spot, ambient and cool side temps and humidity? Inadequate heat and overheating can also lead to regurgitation. You will have to give the snake time to recover from this episode by not offering any meals for the next week to 10 days.