Hello, there,
What good news that you got some relief from the stellate ganglion block,

that looks good for the future and even though the relief did not last long this time does not mean that next time it will be the same.
The best use of these blocks is to have a series of them so I hope your doctor will follow up with more in the near future.
As for the blocks causing spread

I have never had spread from a block and do not know anyone who has had spread from a block----I think that they would not be so frequently and happily used if that was indeed a valid side effect.
Good luck for the future
Tayla