Since snakes are not designed to vomit, and from what I understand a regurge is very hard on them, I wonder if it is possible she ruptured something internally when she regurged and that caused her death ?
I don't have any experience with this in a snake, but I bred birds for 20 years, and every so often a baby would receive an injury to the crop { stomach } which would allow bacteria from the stomach to build up around the crop and in the throat, which was always marked by severe swelling and a foul odor. If not treated aggressively and immediately, this was nearly always fatal.
I'm no vet, but their are similarities that raise my eyebrows.
Please let us know what your vet says.
Gale