JLR and Lablove sorry to read of your complications. After my subtotal removal surgery in 2011 I had minor facial weakness ( HB Grade 2 ) that resolved quickly with decadron. I was told then that the facial nerve can heal for as long as a year after the weakness / paralysis begins. That's the only timetable I am aware of.
I had regrowth of my tumor remnant in Sept 2106 and GK in Oct 2016. Because I had a large tumor originally and facial weakness from the surgery, I was told I had increased risk for facial nerve complications from the GK. 3 months after GK, Jan 24th, 2017,I experienced Grade 4 (on HB scale )
facial weakness with incomplete eyelid closure including exposure keratitis. The ophthamologist inserted a tear duct plug that helped a great deal. A one month, tapered, decadron Rx has helped some. I have complete eyelid closure now and the corneal damage has resolved. My mouth is still crooked but the strength has improved and I no longer have difficulty keeping liquid in my mouth. I cannot close my eye as tightly as the other side, but it works.
I had central tumor necrosis from the GK and that is an edema generator and my last MRI on Feb 10, 2017 showed fluid in my brain adjacent to the tumor as well in the tumor itself. It is unpredictable whether the edema resolves. I have a follow up MRI May 22nd
to check on the brain swelling.
Summary, I can now close my eye, but movement in general is asymmetrical from the corner of my mouth on the affected side to my eyebrow and forehead, though it is somewhat improved subsequent to the steroids. Hope this helps some and good luck