But facial palsy may happen in case the needle touches the ramifications of the facial nerve.
In such case,you can follow the complete restitutio ad integrum with EMG ( electromyogramm) and the total recuperation takes usually 3 weeks to 1 month.
In case of copies, irreversible facial paralysis may occur because of the neurolysis of the facial nerve or its terminations.Check here
Vasodilatators and corticoids can be useful.