Your Doctor would be asking you to contract the muscle so they can get an idea of size and position of the muscle which will help determine dose and position of injections
Hi Nicola The person injecting you is hitting one of your smile muscles that you use to pull down your lower lip, It is a temporary problem and should resolve when the botox wears off. Your injection points need to be repositioned when injecting DAO to ensure this is not a recurrent issue
