Am I immune to Botox? Or just getting ripped off?

20 units of Botox into the "11s" is typical low dose that works on most women, but you should try higher doses if you find no effect with lower doses. The forehead sometimes requires multiple rows of shots to generate smoothness if there are many lines.

You may need more than 20 units to your 11 lines depending on the degree of muscle activity and severity of your wrinkles. Also, if you have lines at rest then the Botox will not be able to completely get rid of them. Some people do have resistance to Botox. If you do not respond at all to increased doses then you may want to try Dysport or Xeomin. Best wishes.