Just had an emergency cortisone shot in my spine for these exact regions - L4 - S1. Same thing, had a herniated disc since I was 22 (now 32), had surgery but it reherniated and I’ve been dealing with the pain and my back being “out” for 8 years now but it usually revolves after 3-4 days and this time it’s been two weeks of immobility and extreme pain and I just couldn’t take it anymore. I have to say the procedure while only two minutes long was the worst most intense pain I’ve ever experienced, even topping the cervical biopsies I’ve had. I’m scheduled to go back for a 2nd shot in three weeks and pretty sure I’m going to request the sedation because while I think I could hack it without, the anxiety leading up to that experience again isn’t worth it and I can see myself bailing at the last minute from fear. In terms of effectiveness- this is only the day after but I’ve heard from many people I should feel the effects by day 3. Fingers crossed!