I have numbness in left arm and leg, persistent headache for 2 months, and today an episode of dropping lip and face numbness. all tests normal?

See a neurologist: These symptoms could represent a migraine, other type of headache, multiple sclerosis, stroke, TIA, other neurological condition, or anxiety. See a neurologist to review your medical history and for a complete neurological examination and diagnostic work-up. http://www.nlm.nih.gov/medlineplus/neurologicdiseases.html

What tests ?: Have neurologist do a careful assessment. Its important to find out what is going on. You need to exclude uncommon causes like venous infarct due to saggital sinus thrombosis