32 y/o fem. had negative mri last yr w/2 mm frontal lobe lesion.now having dull, very brief headaches,nausea,&dizziness. should i have follow up mri?

See a neurologist: A frontal lobe lesion isn't part of a "negative MRI." Keep a log of your headaches (timing, frequency, severity, duration, associated symptoms) and take it to a neurologist, along with a CD of the previous brain MRI. After a neurological exam & reviewing your history, he/she will determine whether you need a follow-up MRI. http://www.nlm.nih.gov/medlineplus/ency/article/003791.htm

I would say no: A 2mm frontal lesion is probably incidental. I would not expect it to cause brief headaches and dizziness. If you have a follow up MRI, it would be to see if there was any change to this incidental lesion. That is not likely.