First off, I have no direct experience with bloods but I understand that "saving it up" is what they typically do. While it makes perfect sense to "connect"
the regurgitation to the constipation, I wouldn't want to assume that's the only possible cause. One thing you can do (assuming they take f/t prey) is to
thaw their prey in water & serve it wet to help with their hydration. A periodic soak wouldn't hurt either, & make sure their enclosure's humidity stays up.