Fredrik,
Xifaxin is indeed one of the more expensive antibiotics out there. Fortunately I have had private insurance but my copays on a 30 day supply have been as much as $40. It’s a highest tier copay drug on most US private health insurance plans. It’s good that it is working and in 2 weeks your skin bacteria will replenish to the point that any lingering fungal infections, if in fact you have one, will be combatted by the rising bacteria count in your skin.
Regarding butt burn: I had it for around a year after takedown and never since- so now about 25 years since I had the post takedown butt burn. I spoke to a knowledgeable pouch expert in New York City who told me that after colon removal, stool has higher alkalinity in it due to there being no colon to regulate the pH of the stool. Why it goes alkaline rather than acidic I don’t know. The Pouch eventually adjusts and either regulates the pH of the stool well, or in other cases, not so well. That seemed like a good theory because mine was present persistently after takedown and then nonexistent, as I said, once I was about a year out. It just petered out and seemed like something inside me was adjusted.
Very occasionally if I eat something super spicy I might feel something but generally speaking I have no issues.
Regarding sugar I do believe it can contribute negatively to butt burn and certainly creates a bacterial feeding frenzy that you ideally would like to control if you are dealing with Pouch inflammation. On rare occasions when I consume some sugary foods there is a noticeable difference in my Pouch function which is not good.
Good luck with getting over the B.B.