Many people wonder what the experience of Botox feels like. Here is a great article:

What can I expect?

People sometimes tell me they are scared that Botox injections are going to be painful and are often surprised at how painless the procedure is.  Also, after about ten minutes, there is no evidence that you’ve had any injections. It then takes about 5 to 10 days ( varying from person-to-person ) for the effects to come on, and then by 2 weeks the full onset will have occurred.