What an interesting problem........
I am not sure that it would a very informative looking on AB for an answer to your problem, but if I can help then I will try.
Firstly this has nothing to do with vitamin deficiencies, neither is it a big deal when one considers the whole picture.
You have ot mentioned any medications that you are taking which could be a factor.
It is almost certainly a viral infection affecting a nerve that runs through the middle ear called the chorda tympani which is a branch of a bigger nerve to the to the face. The nerve supply to your face and mouth depends to a greater extent and causes your symptoms.
What can you do about it? Nothing.