I've come to another dead end with my Kaiser neurology team. They gave me the benefit of a second opinion, including a high-resolution CT scan of the carotids. So far, nothing's showing up on CT or MRI, though symptoms are worsening. I now have a snapping/popping, painful sensation at the base on my skull. It actually makes a sound, so I'm skeptical that it's purely GPN that's causing it.
I keep hoping for a doctor to say, Here's the problem! It's always good news that I don't have any lesions or extraterrestrial parasites, but no actionable explanation for the pain. The drugs are a pain, all on their own. I do remember not to lose sight of the fact that I don't have a more serious condition. Life could be worse, right?