Thank you for your question.Numbness
in the legs may be caused by external compression on the nerve or internal pathology of the nerve itself. It is not clear from your description what the white spots
are. If you can upload report/images of the MRI that would be helpful. Electromyography
and Nerve Conduction Velocity (EMG/NCV) test can find out the exact location of nerve problem.
Management as well as need to repeat the MRI in 3 months depends on what the problem is. Please consult a neurologist
for clinical as well as MRI evaluation.