Numbness in the left face may generally be facial nerve. Numbness in the left face may be caused by facial paralysis, or it may be a precursor to stroke. The other part may be caused by temporary blood supply disorder in the brain. According to different causes, some etiological treatments are carried out. If you have some anxiety, tension, poor rest, poor blood supply to your brain and numbness in one side of your face, you can rest and relax more. Another point is that if it is caused by facial paralysis, we should also have some signs of stroke. This is best diagnosed in the hospital.