Not at all...you continue to apply minoxidil
on whole scalp
, I do not think that you will get side effect on unaffected part. The side effect of minoxidil is irritation in some patients. But it may occur in any where on scalp,affected or nonaffected area. .. So,do not worry..you continue to apply minoxidil. I hope you got my answer.
Dr. Ilyas Patel MD