I was charged for 150 units on my forehead but I don't think that much was used, how would I know?

Botox comes in 50 and 100 units. Dysport is another brand that comes in 300. 150 units of Dysport could be injected into the glabella and forehead and would usually cost about $600(ballpark) whereas 150 units of Botox would be $1500-2000. Not to mention way too much 

Some people charge by the vial instead of by the unit 
You should ask for the price pet unit and ask how many units will be used prior to being injected
The fact you had Botox left over is a good thing 
150 Units is too much 
But is only lasts 48 hrs after being reconstituted even when refrigeratorater 

If you are certain it was Botox than you would definitely know. It is an irrational dose and I doubt anyone would use 150u for any aesthetic purpose. In Australia Botox comes in 100 unit bottles as in many other countries. To my knowledge only in India Botox may come in 200units vials.Did you get ripped off? If it was indeed Botox than you definitely did. This should not be tolerated. I hope you get your money back! Good luck!

thankyou for your question.
This definitely isn't botox as no such dose is used for the forehead. It is most likely dysport . If this is the case you really should have a chat with your injector. You would have signed also a consent form with the name of the product.

Hope this helps

It does sound more like Dysport units which would be similar to about 50 units of Botox. How much did you pay? The only way to know for sure would be to contact your treating provider and ask.

Sounds like dysport may have been used as there are 300 units in a vial of dysport. But you should speak to your treating physician and ask them where and how much of which product was used for your future reference.Good luck from New York City