I'm wondering where to get the Botox injection.

Are there any side effects when performing the procedure on the forehead or between the eyebrows? Can Botox also be injected under the eyes or on the eyebrows? Is it dangerous? It is commonly known that Botox is injected into the bridge of the nose, chin, and square jaw to make them look slimmer; please explain the principle behind this. Are there any side effects from the injection? Do I need to receive injections regularly for the slimming effect to appear? Is there no effect if injected into other areas?