If Botox drips into my eye during injection of my forehead, can it cause severe headache and flu-like symptoms?

This is going to be a difficult question to answer.  I am not aware of any studies looking into the effect of topical amount of Botox in the eye.  As a facial plastic surgeon, I think it would be unlikely that a small drop of Botox in the eye could cause these symptoms.  

It is unlikely that a small drop of botox in the eye would cause such systemic symptoms.  It would be best to consult your primary care physician if you are experiencing flu-like symptoms.

I do not believe that your symptoms are from the Botox dripping into your eye.  The cornea is quite avascular, and even in inner (conjunctival) surface of your eyelid would be unlikely to absorb Botox.  If you had difficulty opening your eyelids, I could perhaps attribute it to local effects of Botox, but I suspect that your symptoms are due to something else, perhaps the flu!Good luck,Dr. Harkaway