Before you have any injectables, you should ask about the qualifications and experience of the person performing the injections. Consult with the doctor or physician's assistant about your expectations, the likely outcome, how long the results will last, and how much it will cost.
The most popular injectable is Botox, which works by immobilizing the muscles that cause expression lines. Dermal fillers are another type of injectable that works by filling in the expression lines and depressions that appear as you get older and your skin thins.
There are many different dermal fillers, which use different materials, last for varying lengths of time and have a variety of uses. Temporary dermal fillers include collagen, Restylane, Hylaform and Perlane. Semi-permanent fillers includes Radiesse and Sculptra. Artefill is a permanent filler.