Jellybean said "No different than any other medication. I know people it works wonders for and some it has done nothing but cause them other issues.
Best to just ask your doctor to see if it’s worth trying for your own circumstances. "
Because you will find some docs are dead set against trying anything new.
That said, I had no luck at all with the numbing injections but I have now been getting botox (from a neurologist) for nearly a year now and have had a 90% decrease in migraines. Just keep asking for a new one if your doc will not think outside of the box.