The flush your feeling is probably a temporary reaction to the steroids
that are in the spinal related injections. I know that the docs tell you that there's not a systemic reaction and that these meds act locally but this simply isn't true. Many people have a brief systemic reaction including feeling flush am having a little difficulty sleeping or feeling a little wired. It usually passes within 24 to 36 hours.
Regarding the decision to avoid surgery it's certainly should be your very last resort. Herniation's can recur and subsequent surgeries become more and more difficult. If there's anyway to control your symptoms with physical therapy
and medications -I think you would be better off in the long run.