My girl Mocha, has Feline Herpes. After getting her eyes looking good, I noticed her one eye would occasionally water, and the vet said it was the Herpes that caused this. Herpes is something that never completely goes away. It can be kept under control, but never truly go away.

I am not sure if your cat has this or not, just giving you my experiance.

I would talk to my vet about it, just a phone call, to ease the mind.