My 13-year-old son has had two fistulotomies (for the same fistula). He is also a perianal abscess. Fortunately, his was pretty much on the surface and they didn't have to cut into the muscle. Had pain meds for about a day and then he was good to go. The sitz baths help a lot. He didn't have to have his packed - was told it is better for his to be open to drain. We kept gauze on the area for about a week but after that, no bandages. We were told this may never heal, as a lot of fistulas do not, but there is a chance it will. He has had this procedure twice on the same area now because it became "active" again. Happy to share any info.
I have had perianal abcesses before due to complications from Crohns. Truth be told, it isn't pleasant. I had an awful surgeon who cut into the sphincter muscles and thanks to him I suffer from bowel incontinence. But, if you have a great Doctor, you should do fine. Ask for pain medication afterwards especially at home. Also, invest in a sitz bath to soak your bottom in several times a day. You may have to pack the wound with a 1/2 " packing strip so the wound stays open on the outside. I am actually suffering from perianal fistulas right now. They are not fun either. Very painful and stinging sensation. Good luck and maybe have a colonoscopy done at some point to rule out Crohns/Colitis.