First of all, let’s be clear that the muscle movements of your eyelid, mouth and cheek are all innervated by the same nerve, which is medically called the “facial nerve” (also known as the 7th cranial nerve). This facial nerve emerges from the “brainstem” deep in the back of your head and travels a long distance from the inside of the skull to the outside of the skull, finally reaching the muscles of the face to innervate the movements of these muscles. In a healthy person, the facial nerve travels with a number of blood vessels, but does not interfere with each other. In patients with facial spasm, some small blood vessels near the facial nerve mutate and compress the facial nerve root. We know that the function of the facial nerve is to transmit a large number of bioelectrical signals that are used to innervate the movements of the facial muscles. In patients with facial spasm, the compression of small blood vessels puts the facial nerve in an “agitated” state, which induces the facial nerve to generate a large number of abnormal bioelectrical signals, and these abnormal discharges are transmitted to the facial muscles, resulting in twitching and spasm of the facial muscles. If you want to go deeper into why small blood vessels are compressed, it is difficult for modern medicine to give a clear answer. All we can say is that it may be related to vascular variation due to individual differences, it may be related to vascular sclerosis associated with hypertension and diabetes, or the reason behind it has not yet been discovered. Since the compression of the facial nerve by small blood vessels is “physical and mechanical”, even changing lifestyle habits and treating underlying diseases such as hypertension are unlikely to change the current situation of compression of the facial nerve by blood vessels, so it is useless to improve the symptoms of spasm. (Note: The above is the cause of the majority of primary facial spasms, except for a few secondary facial spasms caused by aneurysms or tumors.)