Hello, I'm Dr Gary. I've been practicing veterinary medicine since 2007. I look forward to helping with your questions/ concerns.
It sounds like she may be having partial seizures
or sensory seizures
. This can lead to face rubbing, incoordination and drooling. In an older dog like this, the most common cause of partial seizures is a brain
tumor, unfortunately. The only way to confirm this, is with an MRI of the head.
I would try to take a short video of one of these episodes and then make an appointment with your vet or a veterinary neurologist to evaluate it. They will likely do bloodwork to rule out metabolic conditions. If that is normal, they may do an MRI to see if it's a brain tumor. Some of these can be managed surgically, with radiation therapy or with medication (steroids, anti-seizure meds).
I wish it were easier to diagnose, but strange neurologic signs in older dogs can be quite the challenge to figure out and manage.
I hope this helps give you some ideas, let me know if you have any other questions.