You should be fairly safe then! Thankfully, the success rate with a good and experienced vet is high - finding the best vet is the most crucial bit for minimising any risks. Elective surgery always comes with more apprehensions; that is in the nature of the thing!
What you can do to be prepared for all emergencies:
- make sure that you have got hand feed, probiotics etc. handy in case the appetite doesn't come back soon after an operation. At the best, your boy should carry on as if nothing untoward has happened. Please be aware that the poos can take a day or so to normalise again in the wake of an operation.
https://www.theguineapigforum.co.uk/threads/complete-hand-feeding-guide.115359/
- ask your vet when you collect him how soon after the operation he can have painkillers in case he is not picking up and is looking very off.
- check your boy once during the first night to whether the freshly operated scars are OK and he's not biting them. This is much less of a problem these days thanks to much improved operating practices and keyhole surgery.
- please see your vet or an emergency vet if your boy is very apathetic and/or suddenly going of his food at any time; it is usually the sign of an infection taking hold.
- see your vet if there is a swelling in groin area in the following weeks. It is mostly likely an abscess, much more rarely a hernia. Thankfully, there are strong antibiotics these days that can cut through abscesses if baytril isn't doing the trick.
I will keep my fingers crossed that your boy has a smooth ride and can enjoy a very happy married life! My four "husboars" are wishing him the best of luck!