Hi Naomi. Yes, unfortunately Botox results are not permanent. Your injector did not go over expected duration with you?
It's always disappointing to learn that patients have not been properly educated about their treatments before they leave. Or at the very least that they are not given a handout that explains what to expect after treatment. For our Dysport and Botox patients, we let them know that full effect should be seen within 7 days and we bring them back in for a complimentary checkup at 14 days to make sure the results are inline with their expectations. This is not standard for the industry but is in our practice. It helps to avoid just the kind of miscommunication you are highlighting.
Finally, for our patients that are using Dysport or Botox regularly, the effects will normally last about 4 months. Some more, some a little less, but this is a good rule of thumb. Hope this helps and good luck with the next injection.