Should be the same as in humans: partial facial paralysis on one side. You might notice it in an animal by observing one side of the face drooping more than the other, particularly in the eye and mouth.
Possibly an antiviral medication like acyclovir, but really just time. Over time you will start to notice feeling returning to the affected side of the face, as well as a better appearance i.e. not...
Slight or severe paralysis to one side of the face from the eyebrow to the mouth. It is treated with steriods and heals itself in most cases in about a week.