I got Botox injections in my forehead, between my eyebrows. I had a dull throbbing headache for about 5 days, emanating from the site of the treatment. One Excedrin helped, when it started getting bad on the third day. Two weeks later, today is the first day I am feeling much better, after having Flu-like symptoms for the past two weeks. I am amazed that my doctor never warned me of these possible side effects although I asked him up front if I should know anything more about risks. Even more so I am amazed to see doctors on line stating that it must be a coincidence. I know the headache was no coincidence, and I have a pretty strong feeling about the origin of the "flu". (Had the flu shot, by the way).
I don't dare go back to get the next botox shot, it is not worth the risks people describe here.