had something similar done by my neuro
a mix of lidocaine and a corticosteroid in the back of the head (occipital area), deep with a long needle. felt as if it was injected in the center of my head so to speak, i could hear the liquid being pushed into my brain, was a weird sensation.
didn't kill the hits but made them a bit more bearable. the back of my head was numb for over 2 weeks, felt kinda funny.