Is it okay to open up a vial of botox with a bottle opener to get the last drops out?

Thank you for your question and I can understand your apprehension.  As long as opening of the vial was done under appropriate sterile conditions this will not affect your results, and will not compromise your safety. Voice your concerns to your injector, they can provide you with greater reassurance. 

When done properly, removal of the top of a Botox vial may be considered for avoiding waste. The necessity is determined by the way your doctor reconstitutes the Botox - if 100u is reconstituted with only 2cc saline, every drop needs to be saved and used. If you get a nice result from your treatment, you should not worry.Hope this helps you.Dr Joseph