Botox, or onabotulinumtoxinA, is used for three main purposes: muscle spasm control, severe underarm sweating and cosmetic improvement. Botox Cosmetic is used for the temporary smoothing of glabellar lines (also called frown lines), which are the lines between your eyebrows that can make you look tired, unhappy or angry. Don't confuse Botox Cosmetic with injectable fillers. Dermal fillers work differently, plumping up tissues so that lines and wrinkles diminish or disappear (Restylane, Radiesse and Juvederm are examples).
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. Any injection can hurt, but the needles used for Botox injections are very small, so pain is usually minimal. The area can be numbed with a topical anesthetic cream or cold pack 10-20 minutes before the injections are given, so you may not feel much pain, if any.