I've had 3 hernia repairs now ... one umbilical and one inguinal when I was young (12-18 mos) and the last inguinal when I was in the middle of T-38s. I guess I got the lucky genes. I ended up with a patch and plug on the most recent repair
Here's what I took away from it all.
(1) The flight docs will find out about it eventually, probably at the worst possible time (middle of 38s). Mine was also "small" and no pain at all. Still became a "must fix now" issue for the flight docs.
(2) Manage your care. I let them send me from CBM to Maxwell so an AF doc could do the operation (I guess he needed the practice) and I was supposed to drive my own happy ass home a day or two later. Bad Idea. I could have had it done in a perfectly good and modern hospital no kidding 300 yards from my apartment. What the AF saved in the doctor bill they wasted in per diem and travel costs. I was young and didn't know much better, but I should have put up a huge stink BEFORE getting shipped off to MXF. Also not great if you have complications after the fact and your surgeon is 5 hours away.
(3) You don't realize how much you use your abdominal muscles until someone cuts on them. It was fairly uncomfortable for a few days. I was walking normally in about a week and able to fly high-g (for the 38) in 2.5-3 weeks. Not a huge setback to the timeline and I was able to stay with my class.
(4) Take it easy for a few days afterwards. If you do a little too much and something bleeds a little, guess where that blood drains? Think about a GIANT (in my case) pouch like appendage in your lap. Ever watch a bruise turn blue to green to black over time? It's more disconcerting when it's that appendage turning colors. Also a good risk for infection with pooling free blood. If that happens, see a doc. Also see a doc if you have any numbness after (shouldn't be a problem with an umbilical, but they displace nerves and such with an inguinal).
(5) You notice and feel the patch or plug ... for a while. You get used to it, and it goes away.
(6) Arthroscopic is an option for a quicker recovery ... do your research and talk to some surgeons. There are pros and cons.
(7) It's a safe, simple surgery ... the highest risk is the general anesthetic.