Facial paralysis can be caused by damage to nerves through injury, surgery or unexplained syndromes, which make muscles to weaken and droop.

BBC: Facial palsy patients helped by mouth massage

Mia Blackwell, from Bilborough in Nottingham, is one of 124 people in the UK with the rare Moebius Syndrome, which causes facial paralysis.

BBC: Six-year-old Nottingham girl Mia Blackwell cannot smile