40 Units of Botox didn't work?

I suggest you wait about 2 weeks and if you don't see any improvement by then, return to your injector for a followup. I wouldn't give up on Botox, yet! 

40 units should be sufficient. Botox takes 7-10 days to take full effect. Wait the 10 days. If still nothing, go back to your provider.

While it's not common, there is a small percentage of patients who will retain muscle activity regardless of the dosage of Botox administered. If this is your first time being treated, wait 2 weeks and follow up with your physician. He/she can then re-treat this area.

Botox is used to reduce movement in overactive muscles which are causing lines and wrinkles. If there is a deep "11"in the glabellar region at rest (when you are not frowning), it will likely take multiple treatments with botox to make the line go away. This process usually requires injections every 3-4 months for about a year. After each successful botox treatment, you will temporarily weaken the overactive muscles, which over time will cause these muscles to atrophy and improve the 11s.If the area between your eyebrows is still moving significantly after your treatment, you should see your doctor again. 40 units is a large dose, but in the rare male patient with very strong glabellar muscles an even higher dose is sometimes needed. I would wait until at least 2 full weeks after your treatment to make sure the botox is having its full effect.

Botox usually takes a full 7-10 days to fully kick in before seeing your end result, Its best you return to your medical provider if youre still not seeing a difference