Hello Bethany. I'm going to go way way far away out on a limb here. Blockage seems to be the focus of all of this. Some of what appears herein is a bit unpleasant on the eyes, but perhaps, overall, some of this may lead to a future understanding or treatment of snakes in general, when they experience what your snake is now enduring.
# years ago I had severe pain in my lower right side, and swelling, and some symptoms with great similarity to what you are describing of your pet, which like me, has a backbone and a digestive tract. I went for the X-ray, which showed some sort of blockage, and some of my organs above and including the appendix were swollen. The physician informed me it might be either kidney or gall stones, which are enlarged calcium deposits. Now, not knowing if you provide well water or city water, both of which often contain bits of sand, calcium, flouride- AND, not being psychic enough yet to "see" what was within the digestive tracts of all of the food items your pet has ever consumed- it is difficult for me to say if these might be troubles. Either stone, even the little itty bitty ones, when in contact with the lining of the lower digestive tract, can lead to swelling and irritation and inflamation. Thus, 'blockage' occurs. These tiny stones typically have many spurs of calcite growth on them, much like stalagmites and stalactites and other natural mineral formations, except they happen on a microscopic level. From an x-ray, they may not show up at all.
So my physician and I talked a bit, and hypothetical questions/answers were exchanged. Worst case scenario was a $23,000.00 operation to remove my gall bladder. A LidaScan was scheduled for me for a week later. (Where one drinks the radioactive juice and the machines make some pretty color movies of where it goes inside thyne body).
Google is my friend. I Googled LOTS. One of the frequent side effects of having one's gall bladder removed is Diabietes. So I googled more. Eventually I found some natural cures for gall stones and kidney stones. Visually shopping around for the right recipe for me ensued. So I found one which suited my preferences, and followed it. Granted, the human body has two bowel places to release from, which is one of our differences from the snakes. That aside, I fasted for 9 hours, then consumed carrot juice for 6 hours, then water for 4 hours. This was followed by consuming one cup of pure fresh lemon juice AND 2 cups of Cold Pressed Olive Oil within a 2 hour period. Then off to bed to sleep. It is a wretched thing to try to drink straight olive oil, and there comes an overwhelming urge to hurl. That aside, I did it and kept it down.
The following morning, about 11 am, I put a piece of cheese cloth across the basin just under the commode seat, to catch my waste. There was a lot of waste; chunks of red licorice I'd eaten 6 weeks earlier, amongst other things. As the recipe suggested, I took the mess outside and sprayed it over a pail with the water gun. One of those rubber glove operations. Long story short, I stopped counting when I got over 300 small gall stones, the products of having consumed well water and other non-distilled waters during my lifetime.
Now I realize your pet and I have our differences, but I can't help but wonder, what kind of fat/oil would pass rapidly through a snake? Could it be force-fed through a syringe with a tube? I used to force-feed some of the snakes I had many eons ago, utilizing this method. The tube was standard aquarium tubing, the cut off end which would enter the snake was heated with a flame (bbq lighter- keeps the fire away from the fingers) to smooth down the cut/potentially sharp edge where the tubing is cut at.
I should also point out here I am not a vet, or someone trying to sell you lots of bills and medicines I make money on, nor that I have any clue whatsoever if any of this would ever work in an instance such as yours. What I do know is that for $20.00 in ingredients, my LidaScan came back negative, I got to keep my gall bladder, and I saved $22, 980.00.
But then again, I'm the newbie, and probably way out of line.
Kind thoughts and prayers for your pet.
dave