Everyone is different in how they respond to blocks (like all things CRPS related), and even the technique of the doctor can make a difference. I literally woke up screaming about my shoulder after my hysterectomy. I did have a rotator cuff tear, but it was severe CRPS pain that was the issue. I also had swelling, it got very hot, and I had a bad rash. My shoulder still has the structural issue, but 5 weeks after the block, the spread hasn't returned.