The results after the Botox injection are expected to last for about three to six months. The binding to the nerve that causes muscle paralysis is permanent. As the muscle gradually begins to regain its mobility, the wrinkles or hypertrophy begin to re-appear. The re-appearance indicated the effect of the Botox injection is wearing off and another shot may be necessary. With continued use of Botox, the lines and wrinkles gradually become less severe as the muscles begin to shrink after an extended period of inactivity.