i have had a jpouch for 25 years and am finally going to have it removed because i have fistulae that won't heal, but i can tell you that bad butt burn has been a persistent problem. sometimes, it is so severe that i need narcotics to fall asleep. the only thing that helps is being religious about sitz baths--4x day--and barrier cream (i use calmoseptine, and yes it is a mess) every single time i go.
not having it anymore is the only reason i'm looking forward to a permanent ileostomy.