A wrinkle in the skin is typically formed perpendicular to a contracting muscle located directly beneath it. For example, the muscle in the forehead is a vertical muscle, and when it contracts (such as when you raise your eyebrows), the lines that form (wrinkles) will be horizontal.
Botox is not a dermal filler. Instead, it blocks nerve impulses that cause muscles to contract and cause forehead wrinkles.
Likewise, the two muscles that are responsible for the frown lines are positioned slightly horizontally between the eyebrows, so when they contract, the frown lines appear vertical.
Botox Cosmetic is injected into muscles, where it blocks nerve impulses to those tissues. The muscle activity that causes the frown lines is reduced, and a smoother look results. Without a contracting muscle beneath it, the skin has a difficult time wrinkling.
Facial lines that exist when your face is totally relaxed are not very good candidates for Botox. These lines are better handled by the dermal fillers. Botox can frequently "soften" these lines but not always get rid of them.
The injections take about 10 minutes, and you should have no downtime afterward.
Normally you would see improvement within a few days. Botox requires two to four days for it to attach to the nerve ending that would normally stimulate the muscle to contract. The maximum effect usually occurs at about 10-14 days. Therefore, whatever effect is obtained two weeks after the injections should be considered the maximum effect that is going to occur.