This hair loss question was answered by Dr. Robert True of New York, NY who is a member of the Coalition of Independent Hair Restoration Physicians. His professional answer is below.
How long does numbness last after hair replacement surgery? Is this normal?
It is common to have temporary loss or change of sensation to the scalp during and after a hair transplant procedure. The most common area affected is the top of the head, or recipient area.
Occasionally, the area above the donor incision may also be affected. The tiny nerve endings located superficially throughout the skin are traumatized by the hair restoration procedure resulting in the sensation change. The sensation does return to normal, but commonly this can take from 2 to 6 months. Rarely, it may take longer and very rarely, there may be small areas in which the sensation does not fully normalize. There is nothing that can be done to speed this process.
Recovery of sensation is often associated with minor tingling, prickling, or itching sensations (signs of healing).