A doctor injected half of her face with Botox to show viewers exactly what it does. In a viral video, Dr. Bita Farrell explained that she made herself into her own "lab rat" by drawing a line down ...

Dr Farrell then tries to use the muscles on both sides of her face but finds herself unable to shift those on the Botox side. 'I'm really trying to pull this side,' she says, obviously struggling.

California-based Dr Bita Zadeh Farrell treated herself as a 'lab rat' for her experiment which saw her only use botulinum toxin on the lower facial muscles on her right side.