Botox generally lasts about 3 months however depending on how it was injected, what the dosage is, how it was diluted -it can last longer or shorter than 3 months. Some people find they need more units as they age or that it does not last as long.
I commonly inject Botox for headaches, so it is actually more frequent that headaches improve with Botox injections however infrequently headaches can occur with Botox injections. It should only last a few days. Make sure the person who injected you is qualified to be doing Botox injections and they are getting their injectable from a reputable source. There are cases where practioners will purchase their product from out of the US and it is uncertain what the strength is. If things get worse in the next two weeks, seek medical advice.
