involves involuntary contractions of muscles of one side of face.It usually begins around the eyes and can later involve other muscles supplied by the facial nerve
. Its usually seen on one side only although it can occur on both sides of face.
These movements cannot be voluntarily suppressed like in a condition called Tics and can continue even in sleep.It is thought to be due to blood vessel pressing on the facial nerve although it can be due to other causes also.
It is not paralysis
like you fear. Effective treatment is taking Botilinum toxin injections or doing microvascular decompression surgery if there is pressure on the facial nerve as earlier mentioned. It is possible to maintain reasonable control over the movements with treatment.
Hope this helps!