Bell's palsy vs. facial nerve palsy. different?

Not exactly the same: Not exactly. A bell's palsy is an acute peripheral facial nerve palsy of unknown cause, presenting with one-sided facial paralysis. There are also central facial nerve palsies and chronic facial nerve palsies, neither of which are bell's palsy. In short, all bell's palsies are facial nerve palsies, but not all facial nerve palsies are bell's palsies.

Often: Misdiagnosed, bell's palsy is a type of facial nerve palsy when the cause is unknown. In order for a facial nerve palsy to be correctly labelled bell's palsy, an appropriate evaluation with imaging studies needs to be done.