Has anyone had a nerve block injection?

I got a nerve block injection into my occipital nerve yesterday. Initially my head was numb; dentist like, can’t feel a damn thing, watch me smack my head numb. So then the numbing agent wore off and I just kind of felt a huge void in the back of my head. Today, however, I have been suffering one of the worst headaches I’ve had in a long time. The injection was an attempt to stop the headaches, but here I am with the mother of all headaches. I have Googled occipital nerve blocks and occipital neuralgia (my official diagnosis), but I am wondering if anyone here has any first hand experience with this type of treatment.