Botox^® manufactured by Allergan, has a very good track record of safety in over 20 years of clinical use including cosmetic use and use in children with cerebral palsy to release tight muscles, blepharospasm (facial tics) and a wide range of other uses.
The most common side effects are temporary and localized to the area of injection. These include soreness or mild bruising, (which can be easily covered with makeup), headache and less commonly, you may develop a heavy eyelid lasting 1-4 weeks which your doctor may be able to treat. There have been no permanent side effects of Botox^® reported.       
Botox^® is not recommended during pregnancy or breastfeeding or for patients with neuromuscular disease. We discuss all the risks in detail during the consultation process.