Hi, I'm here! lol
Not much time to reply, but yes, I do suffer with Occipital Neuralgia.
But I haven't yet considered having my occipital nerve/s cut, so I can't really help you regarding surgery and post-op expectations. It would be a last option for me, according to my neuro, and I don't need to go that far yet, as my pain is mostly controlled by nerve blocks.
I guess the main suggestion is for her to tell her surgeon that the pain is still there, and hope he listens.

~Jaime~