Have you tried any lotions or creams? There’s a lot out there you can try. Barrier cream, which prevents the acids from touching the skin as they exit. Or calmoseptine lotion (not sure if the spelling is correct) which has some menthol that cools the area. I use a bidet which works well. Some people say pepto helps with diluting the acids for when they come out.
Another option are wet wipes (instead of a bidet, or if you’re away from your toilet and you need to clean up) or Balneol, which is a general cleanser that you can use with any toilet paper. That will moisturize your skin after a bowel movement.
Also, are you taking any Imodium or anything to decrease the number of stools you have? That might help if you’re going less.