Botox acts by relaxing the muscles. If a muscle does not fully contract, the skin over the muscle does not wrinkle. Repeated contractions of the muscles can cause deep wrinkles in the skin, which eventually will produce a permanent crease. After that happens, even Botox will not fully eliminate the crease. If Botox is injected at the first sign of wrinkling, a deep crease will never develop.
Dec 12 2008