Wild agree with Brinjal, don't overdo it. My mum had Botox without telling us and none of us noticed! (She hasn't bothered again). BUT when someone has had it regularly you can definitely tell - their face gets shiny somehow, their eyebrows start pointing up Spock-like and they just have a kind of blank expression. Think Katie Price.
Old colleague of mine is the CEO and President of the Co that makes it, Allegeren, one David Pyott, a Brit, working in San Fran. He has received a CBE - for which we cynics named his award as "Cheeks Botoxed and Exhausted."
I know it's used in medicine, but I had no idea where people go for cosmetic purposes. A friend of mine left disabled by a bleed from an inoperable brain tumour has it in her useless arm in the hope of reviving it to a degree. It's not working. :o(