Bell's palsy is a facial mononeuropathy that has an acute onset. With time, many patients recover well. However, as the fibers of cranial nerve 7 grow back, some end up innervating structures that they did not originally innervate. A common example of this is fibers that originally targeted the orbicularis oculi growing back to innervate the orbicularis oris. That is what happened in this man's case. Consequently, whenever he blinks, you can observe small movements of the left side of his mouth. This phenomenon is an example of a synkinesis. In the video clip below, the unnecessarily large green arrow points to the area where you can see mouth movement every time this man blinks.