I've posted quite a few times about my abscess/fistula surgery. They don't "think" I have Crohns, but they always say they can never be sure, that Crohns can "do whatever it wants."
I had a rubber band seton placed, it looped up just from the inside of my anus about 2 inches up. My CRS did not tighten it for a month or so, just allowed it to drain the abscess. It was sore and uncomfortable for a while but felt so much different to me than the pain of the abscess and fistula that I had had for so long, that it was tolerable for me. My "knots" hung from the bottom of the loop and really didn't bother me if I had the gauze pad placed properly. Are you using gauze? It applied enough pressure that I eventually just couldn't feel it, kind of like how you forget you are wearing ring on your finger.
I also had an incision, to the right of my anus, to allow the abscess to drain and heal from the inside out. It freaked me out in the beginning, when I saw how bit it was- but I hear it wasn't so big compared to other people. My incision was about 2.5-3 cm deep, and I'd say about 3 cm wide, cut to the right of my anus. It has since healed up and you can't even see the incision, it has kind of just become one of those little "wrinkles." I still have some drainage, and have to wear a gauze pad, but the deep abscess is gone.
My CRS said this may be my new normal, I'm not sure yet. I have to go back and see him again in 2 months- he wanted the scar tissue to heal a bit more before he makes a final decision ( I still have a hard bump where the abscess/seton was, which I don't think is normal, but he doesn't seem too concerned). Overall I feel much better and I loved my seton, I felt sad when it fell out. Weird, I know. That little sucker helped me feel better!
I hope you have a positive experience! I can only speak for myself. Good luck!