My reversal surgery was harder than my ostomy surgery. I was in the hospital longer and had more pain than with the original surgery. I am nearly 3 years after reversal and am glad I was lucky enough to have the reversal. I developed severe Ileus and was in ICU for 10 or 12 days.
Advice, walk as soon as you can and as often as you can, take baby wipes and diaper cream with you to the hospital, consider adult diapers for sleeping. My body did not sense the need to have a bowel movement for several weeks. My surgeon's PA told me to expect accidents; they will happen, it did to me. If they are doing it open, it is not common to develop adhesions. I had 3 more open procedures after reversal, each being harder to recover from. Take time off from work if possible, I went back to work quickly and it was miserable but manageable. I am a physician so no heavy lifting.
In my case, they always went through the same incision and each time my skin was harder to heal. Eventually, I had a plastic surgeon redo my incision and I look as good as I can.
Good luck, take it easy after surgery and WALK to get intestines working.