Bell’s palsy causes temporary paralysis, or palsy, of facial muscles. It occurs when a condition, such as a viral infection, causes inflammation and swelling of the seventh cranial nerve (the nerve that controls facial muscles). With Bell’s palsy, your face droops on one side or, rarely, both sides. You may have a lopsided smile, or an …
https://my.clevelandclinic.org/health/diseases/5457-bells-palsy