Re: occipital neuralgia....will the pain go away in 48 hrs?
If it's really occipital neuralgia, then anti-inflammatories (which cortisone is), muscle relaxers and pain killers help. Have you tried rotating moist heat (hot moist towel from microwave) and ice on the lump? I would call my PCP tomorrow for advice.
It sounded like O.N., but I could have thought you would have gotten SOME relief from the injection...that's pretty strong stuff.