BOTOX Cosmetic usually lasts about 3-4 months. Even though the administration of the BOTOX Cosmetic should be the same from office to office, there is definitely some variation in how physicians reconstitute it and how long they keep it on the shelf. If you are experiencing movement after 6 weeks then you should speak with your physician about your concerns. Sometimes a touch-up can be performed. If it continues to be a problem, then try a different office. Only rarely does a person metabolize the BOTOX Cosmetic that quickly, but if the same thing happens at another office, that could be the case.