So apparently in Thay they just rip your clothes apart to remove tattoos, which is really unfortunate since I was wearing a custom tailored and enchanted outfit at the time and now it's basically ruined.
Pics:
BEFORE
(https://i.imgur.com/yNN0KMd.png)
AFTER
(https://i.imgur.com/TelTYJI.png)
Reequipping and whatnot doesn't fix it. If it's not fixable, could we at least get a warning dialogue (also how about the NPC tells us how much it will cost, to boot?) telling us to remove any armor that has a part on the affected area, because it could be permanently changed?