I would SERIOUSLY consider a dose of Flagyl(Metronidazole). This has stopped a few regurges I've had in the past DEAD IN IT'S TRACKS!. The snake could very well have a stomach/intestinal pathogen(s), such as Entamoeba invadens, Trichomonas. Balantidium, Rhizopoda, Flagellates, or Ciliates. Flagyl will open a can of "whip-ass" on ALL of these.
I strongly suggest you take it to a qualified reptile vet for diagnosis if you bring a fresh stool sample for a "fecal floatation".
Constant regurgetations will certainly lead to it's death if left untreated.
The proper dosing is 25 to 50 mg. per kg. of body weight. This drug is very well tollerated by snakes, and I go with the higher 50 mg. per kg.
You REALLY need to stop messing around, and get the snake to a vet, where he/she can DO something for the snake. I would have done something about it long before this.
BTW,...DO NOT offer the snake ANY more food until you get it you get the snake medicated, more meals will just send the snake further down the tube until it dies. If you do something SOON, there's a very good chance that it will thrive, and do well from then on.
hope it pulls through okay!, let us know what happens.
best regards ~Doug
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"Better to be silent and thought a fool, than to open mouth and remove any doubt!"