A good friend of mine/exceptionally bright BP Breeder, Brian Grundy, from "For Goodness Snakes" helped me the last time I had a regurge. He was a vet tech for an exotic vet for quite a long time and has been keeping and breeding Balls for ever.
My normal girl I gotten from a private party had not eaten for the first 6 months I got her. All husbandry in this rack was spot on in that all the other animals in this rack were eating fine and were very healthy. Well she finally took a decent size mouse one day (she wkas around 1600g at the time). Btw, I know what u mean about the smell.. I think that was the worst.. ever. Lol. Poor thing. Anywho, this is what Brian told me:
He said that anytime he had seen this happen in his animals or others while working at the clinic, 90% of the time they would find some kind of parasite in the feces. He told me to give this a shot, and ir it didn't work then no harm no foul and let it rest for a month and try feeding again.
Told me to go to the local feed store and pick up a product called Panacure, which is a parasite/worm eradicate'r for horses or other livestock. Its a white cream that comes in an oversize syringe with a plastic nozzle. He had me hold her behind the head and stick the end of this nozzle into the back of her throat (gently obviously) and administer around a teaspoon or so. Then repeat every 5 days I believe for a month.
Once I did this, I tried another meal and she has been thriving and eating well ever since.
Id definetly just try another meal a month from now before doing this and see if she keeps it down. If there's another regurge then it might be worth a shot. Best of luck and I hope u are able to figure it out!
As stated above there are obviously other things that can cause this. I.E. heat spikes, stress, etc. I just wanted to relay what worked for me. Sorry about the novel!