Jinny--I wish you all the luck as you face your fear of needles headon. I also have that fear, although it has been controlled after my many injections over the years.
I'm assuming you are young and I'm definitely old, so you are not required to listen to my advice. I've had probably ten or more of the back injections (cortisone, pain meds, etc.) and my advice is ask for something that will relax you or even put you under. Have you ever had nitric oxide at the dentist? Something like that. Call the pain clinic ahead of time and ask for a relaxer as powerful as they can give and reiterate your fear of needles.
The tablets you took prior to your op was just to keep you from climbing the walls thinking about what you were going to have done to your body. You were very relaxed by the time you got the real anesthesia. Why do you think it only takes a second or two counting backwards from 100 before you are out in the operating theatre?
When I do have the injections, I try to concentrate on something else. In my case, I recite poetry back to myself until I get drowsy. "Kubla Khan" by Coleridge is a favorite of mine.
So, now you have some stitiches and I'm assuming you don't want any more and that you hope the injections give you relief. I hope so, too, but remember, they are only temporary and may not work at all. So, don't get your hopes so high that you are crushed if the worst happens.
You can write to me with a pm whenever you want and I'll try to answer your questions. Best of luck with everything.
lsg