Botox (onabotulinum toxin A) reduces the appearance of fine lines and wrinkles by temporarily blocking the contraction of select facial muscles. Botox is injected using several small injections into the muscle with a very fine needle. As Botox takes effect over the next several days to weeks, the overlying skin becomes smoother. Botox specifically treats the wrinkles that occur during contraction (dynamic lines). Wrinkles that are present at rest (static lines) are often not initially eliminated, but can soften with time and with regular injections as the underlying muscle stays relaxed.