Hi KL - I had Bells Palsy that came on pretty quickly about 3 weeks before I delivered. It's shocking and horrible isnt it???
I always struggle with full ears and sinus pain so mine could very well have taken a while to come on too. I first noticed it when I was brushing my teeth and couldnt purse my lips to spit. I went to the chiropractor with no results. My next appt was with a neurologist who tested me to diagnose Bells Palsy and not something more serious like Guillain-Barre Syndrome. Bells Palsy is a result of the 8th facial nerve (the nerve that exits right in front of your ear) gets constricted because of inflammation. It's common at the end of pregnancy because blood volume is significantly higher then - it is also readily associated with a virus like Herpes I or II settling in the nerve.
There's not going to be much you can do except to treat the pain - I had most of my pain in the boney area behind my ear. I found that alternating cold and hot compresses helped me. I was thankful that I could close my affected eye but the rest of that one whole side of my face was completely numb and immobile.
I did a lot of reading about treatments - since you are pregnant and time has already passed, antivirals are out unfortunately. Steroids are often given as a treatment but there appears to be some dispute over whether or not they work or justify the risk of high doses of steroid. I have a medical condition that required me to have IV steroids administered during delivery and afterwards. It may be anecdotal, but my face started easing in the hour or so after the first dose. It was small but I could twitch the corner of my mouth on that side and felt some tingling in my cheek and it kept getting better after that.
The neurologist was spot on about healing time and permanent damage. After 4 weeks people said I looked back to normal - my smile was straight etc. It took a good 6-8 weeks before I felt more normal. I still have some facial weakness and numbness although no one else can see it. I get a numb feeling of fullness in my cheek and and along the lash line in my eyelid and I have to think about what I'm doing to purse my lips.
The majority of the time I am completely a-symptomatic.
It's REALLY hard and I completely understand. I felt so incredibly disappointed and self-conscious. It was a big blow to my self-esteem and I just wanted to hide. As if being as big as a bus and ready to deliver werent bad enough - this had to get added into the mix.
I'm so glad to hear that you are healthy and that your baby is healthy. Before long this will all just be a distant memory compared to the beautiful love being added to your family.
All the best -