I have also had my J Pouch many years (29). Around 5 years ago, I felt a little extra something there and got opinions from my GI, a dermatologist and a colorectal surgeon that it is a skin tag. To me it felt like a small lump. I was told by all 3 that it's harmless. The colorectal surgeon told me that any attempt to remove it would be dangerous and could compromise the muscular integrity of the anal sphincter and impact on continence. So I ignored it.
It's not painful now, but at one time it seemed a bit sensitive to a vigorous scrubbing.
Don't be afraid to bring it up with your GI/dermatologist.