I had the same problem with my dougther putting a letter (2x1 tile) sideway into the hand of a knight using it as a messenger and leaving it like that for the night. I just removed the tile and put it on top of it, left for a day or two and it's now perfect. Maybe it will work for you too.
Hi, I'm new here, been reading the forum for months but never posted anything so can't send out private messages. Would you mind sending me the file/link at the address in my profile?
Thanks in advance