If I'm correct Cyndy, you had a SGB and that injection blocks the Sympathetic Nerves, which in turn MAY reduce pain, swelling, color, and sweating changes in the upper extremity. The arm should feel warmer. The block MAY improve mobility. They are done as a part of the treatment of Reflex Sympathetic Dystrophy (RSD) or for Herpes Zoster (shingles) involving upper extremity or head and face.
They can be diagnostic (for RSD) &/or therapeutic.
I've never heard of general anesthesia being used. Most ppl are either awake
or have IV sedation (which is what I had). If it is successful your eye droops and the extremity gets nice and warm on the side the block is on.
My blocks were Bupivicaine injections.
Everyone is different and so they react differently. Some people need 2-4 injections - I know one girl who had over 50 over a 3 year period. She stopped having them when they stopped working.

Hope this helps. Hope