5 months seems too soon to give up, I never heard 3 months before. I never had complete paralysis (mine was House - Brackmann grade 4) but I began to see some recovery in about 3 months following a taper of Decadron ( a steroid used for brain swelling.) I am approaching 2 years since the gamma knife treatment that caused the facial weakness and am now grade 2 paralysis and can close my eye completely, so I would say my recovery has been a combination of steroid treatment and natural recovery with time.
Oct, 2016 - GK after AN regrowth from radical subtotal removal microsurgery in 2011
Jan 2017 - Facial weakness onset late in the month - mouth droop, no eyebrow movement, no lid closure
April 2017 - mouth droop and lid movement improved
July 2017 - synkinesis set in, termed jaw - wink syndrome by an ophthamologist
Oct 2017 - MRI showed 100% resolution of swelling of tumor and the brain adjacent to the tumor
Jan 2018 - mouth droop still present but not noticeable, eye closed completely
Sept 2018 - grade 2 facial weakness seems permanent, 2 year MRI set for Oct 22
There is a Facial Paralysis Center at Univ of Pittsburgh Medical Center. Possibly they have information they could send you or even refer you to someone closer in distance for consultation ( you indicated Sacramento as your treatment location. )
https://www.upmc.com/Services/ear-nose-throat/services/facial-nerves-and-plastic-surgery/facial-paralysis-centergood luck