It is caused by nerve paralysis following a virus, often whilst under stress or overworked and causes a “drop” down one side of the face. The eye cannot close and such things as eating and speech can be very difficult. However, the person has usually gotten over the virus by this time and is feeling much better but they look facially disfigured.
Now, for the majority of sufferers, frightening as this first appears, it is only a very temporary problem, lasting three to four weeks for the nerves to begin to restore themselves. A course of Echinacea, valerian and ginseng mixed (I can do this for you) for a few weeks, with 2000mg evening primrose oil and a good multi-vitamin daily plus a good B-complex, should boost the immune system and rebalance the body to aid a speedy recovery, which should be totally complete by three months tops including a re-boosted immune system again.
The facial muscles can be exercised with over pronounced facial movements whenever you are sat doing nothing, so lots of winking, oooing and aahhing!!! Only for a few does this become a long term problem and if no recovery is obviously progressing after 2-3 weeks, then medical help should be sought.