When using Botox® injections for wrinkles, a cosmetic surgeon will inject a miniscule amount of a purified protein toxin into a facial muscle using a very fine needle. A few days after the Botox® injections, wrinkles and creases will begin to soften and often will disappear completely. This effect will typically last three or four months. After the effects diminish, the process can be repeated. Many patients require less frequent Botox® injections over time. Botox® injections for wrinkles act upon the muscle beneath the skin. The toxin works by preventing nerve impulses from reaching the muscle, forcing it to relax. Since the muscles can no longer contract, the frown lines associated with each muscle are reduced.