I've tried Botox, albeit without success, but the injections are often given at the headache center that I go to (they don't really consider it a last resort) and I've spoken with many people who have had much success. I can tell you from experience that, although the prospect of facial injections is daunting, it really isn't very painful. I assure you that the idea of the injections there is worse than the actual experience. You'll do fine :)
One question that I have though, is what non-drug treatments you have tried. If you haven't looked into these already, I recommend that you talk to you doctor about
nerve blocks, nerve stimulators, or more experimental drugs (like Lidocaine as a pill, nasal spray, or IV infusion--or many others). I don't know exactly what you have tried, but try not to look at botox as your last resort.
DX: NDPH, Bipolar 2, Recovered CRPS
RX: Lamictal, Abilify, Provigil, Clonazepam, Rozerem, Emsam
PRN: DHE IM, Droperidol IM, Toradol IM, Haloperidol, Zyprexa, Lodine, Thorazine, Zofran