A blood test showed high anti-mag. titers. does this mean i have anti- mag neuropathy?

Not necessarily: A diagnosis of neuropathy depends on your having symptoms and signs of peripheral nerve dysfunction: numbness, tingling, other abnormal sensations, perhaps muscle weakness, and pain. If you don't have symptoms, you don't have neuropathy, but you may be at risk given the result of the blood test. Why was the test done? What brought you to the doctor? These may bear on your question.