The main trunk which supplies all the facial muscles is very rarely if ever divided accidentally, it is occasionally (bruised)giving an "odd looking face for a short time, day or so, but this soon recovers.
Small branches may be damage, which may give partial paralysis of either lip or eye, but this disappears completely in the majority of cases within a week or so. Most surgeons now use an electrode to stimulate a piece of tissue before they cut it to be sure that it doesn't contain nerve tissue.
Most parotidectomies leave no sign of facial paralysis which is permanent.
Don't worry.