Docs in pain clinics can often schedule you within a few days after your first appointment if they perform the blocks in house. (You might need a referral from your doc at home, along with a prescription for the block.) If you go with a doc that uses a surgery center, it might be a bit more difficult scheduling quickly. There is also the issue of getting confirmation that the procedure is approved by your insurance--if billings is not in the US, that might be tricky to get done as fast as you need. I would NOT recommend an ER--those docs would not perform them regularly enough to do the best job. If you could get into a teaching hospital and have a spine surgeon perform the block, you'll probably get a good result (if you're still capable of getting a positive reaction.) A former doc of mine was a spine surgeon earlier in his career and his stellate ganglion blocks were vastly superior to others I had undergone.