I'm not the best person to ask but the nerve they numb up for dental procedures is a branch of the trigeminal nerve. I had trigeminal neuralgia in addition to PMR. My trigeminal neuralgia symptom at the worst was unimaginable facial pain. A dentist couldn't even touch my face without causing severe facial pain when trigeminal neuralgia was active,
https://www.mayoclinic.org/diseases-conditions/trigeminal-neuralgia/symptoms-causes/syc-20353344
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While trigeminal neuralgia isn't treated with Prednisone, my facial pain decreased when I took Prednisone. It was hard for me to accept that it wasn't somehow linked to PMR. I referred to trigeminal neuralgia as my "inflammation alarm." Trigeminal neuralgia was more active when PMR was active,

I had brain surgery for trigeminal neuralgia. The neurosurgeon said it was a vascular problem but not anything like GCA. The neurosurgeon said he did the best he could to fix the problem but now the entire left side of my face and scalp including my left eye and the left side of my mouth are all numb. The neurosurgeon also said that Prednisone was probably helping the inflammation in the area near my brain stem where the problem was.