From my experience, I only had a series of 3 nerve blocks. I too felt great right after the nerve block, but the pain always returned within 48hours so we only did a series to 3. Reason being was because it's effects were so short-term that the risks out weighed the benefits. After the nerve blocks I tried ketamine. I would look into that if the series of 3 dont work out for you.
I hope you get some long-term relief soon.
Sarah