Jethro got neutered at 7 months old and everything went very smoothly. However, 5 days later he had the first potty accident in 2 months(peeing). Do you think this could have been possibly related to the neutering? He has been very reliably using bells to tell us that he needs to go? Furthermore, it wasn't that he needed to necessarily go, he had just been taken outside less then an hour before the accident, and he usually holds it for at least 2 hours. I am worried its marking related.

Thanks for any advice.

If it is a marking issue- don't panic! Their hormones don't magically go away after they're fixed. It can take up to two weeks for their hormones to settle down after getting spayed/neutered If you're REALLY concerned, just go back to basics. Reward him with a yummy treat outside when he does his business- and if he does have an accident let him know you disapprove. Did he have a marking issue before the surgery?