My advice is- your snake has made it to an old enough age that you know this regurge was meal-size-related- not some sort of birth defect or abnormality or weakness that it will eventually succumb to. One regurge, while serious, is surviveable. Once you get two or three, the snake's chances of survival drop rapidly. I would treat this very, very conservatively. As Susie says, after the initial waiting period, drop back to a size smaller mouse than the hoppers you have been feeding. I'd do two to four meals of that small size even before returning to hopper size. I might not ever feed double hoppers again- I might instead go to a small adult. The size hoppers I use are about 14g- that's equal to a pretty big adult mouse if you double it. I would also slit every mouse from now on, forever. Good luck.