@turkay-- I think those side effects may also be due to the cortisone, or it may be that you are sensitive to lidocaine injections and get side effects because of it.
I personally get lidocaine injections for my migraine and I've never had any side effects except for some temporary pain at the injection site. I get a lot of relief from them and I have heard the same from my friend who is under the same treatment.
I think lidocaine is one of the safest pain management medications in terms of side effects. But everyone does react different to the same drug.
Is it possible for you to just get lidocaine injections? That would help you figure out if the side effects are really from the lidocaine or not.