Have you been getting a good source of easy-to absorb b12 with your therapy? Gerson therapy (which included coffee enemas so often) added b12 in to help the liver. Coffee offers almost all the ingredients needed for healing/making Glutathione in it, but the b12 content (the mineral cobalt) can be lacking, especially if starting from a poor health standpoint.
Best is a methylcobalamine, and great if it's in a liquid or gelcap. It's best absorbed rectally, which is similar to a b12 shot- and please start with a low dose , perhaps 3-5x the RDI (recommended daily intake) valve in your country, so you can observe yourself for changes in sensation/well being without overloading yourself.
The liver uses b12, methyl compounds, folate, etc, to separate homocysteine (the part of the blood carrying toxins back from the circulatory system for cleaning out) back into free cysteine. The toxins are usually released with the bile for elimination.
My thoughts are that your system is likely trying to produce and eliminate more bile than you have resources to properly process, and it's showing up in kidneys too because they're the secondary backup to the liver.
Have you tried detox baths (like a magnesium sulfate/ Epsom Salt soak, or Bentonite clay bath), activated charcoal tablets.. Bentonite and psyllium husk drinks..?
Activated charcoal should be available in your local drugstores, or your personal hardwood campfire (just powder it for drinking!). It should help absorb the excess bile and keep the toxins from getting re-absorbed into the small intestinal wall and continuing the irritation. Just remember that you'll need a little more salt and good fiber like gentle foods, Apple and carrot, and lots of water when using AC.