It seems that Mayo Clinic is willing to discuss the connection to viral infection, but there is also possibly a relationship to vaccine ingredients such as mercury and aluminum. If the palsy is related to simple inflammation of a nerve due to a virus that is one thing. If the palsy has central nervous system origin that is another. Once again modern medicine has delivered an intervention that is likely worse than what it aims to "prevent". I like the following resource on explaining Bell's Palsy:
Forrest has come up with a pretty good alternative explanation for Bell's Palsy. You wouldn't necessarily thing metal toxicity could be "one-sided" in the brain, but his explanation for why that might be so is pretty plausible.
I don't know the ingredients in the "coronavirus" vaccine that was associated with the Bell's Palsy so I wouldn't know for sure if the metal in the brain idea is valid.