I had a the exact same thing happen with a batch of fat mice -- several animals got steatorrhea (fatty, oily poop) after I stupidly fed them these gigantic retired-breeder mice with WAY too much body fat.One of the snakes was a young male who puked up the mouse, like yours did, and then shed out all of his color at his next shed cycle to become the coolest black and white.
I don't think that he had a bacterial infection, though; with that animal I was lucky enough to catch and clean him up immediately, so although the cage was very nasty for a few hours he wasn't sitting in it long enough to get septic. He also never showed any signs of systemic infection and ate just fine after that incident.
I do think it's metabolic in some way, though, at least in these cases ... I've heard more than one person say it's happened to their snake after a "bad" or fatty batch of rats, so I wonder if it may sometimes be related to a temporary lipemia ..? I can't for the life of me think of a mechanism though.
What baffles me about it is that it only seems to affect the lighter pigments in the pattern (browns/yellows -- pheomelanin, I believe) while sparing the black pigments (eumelanin). There must be something in the way these two different pigments are synthesized that might give us a clue ...![]()