Typically as the nerves grow back into a surgical site there will be increased tenderness, shock like sensation and possibly itching. This is very normal.  Scar maturation takes a full year, after which the color becomes pale, scar thins and softens.  For the tummy tuck, the dissection is very extensive so the regrowth of the nerves can take a long time.  To desensitize the nerves you can massage and apply silicone sheets.  I find the topical sheets of silicone by Newgel and similar companies may provide more padding and than one would get from the liquid silicone alternatives which are applied from a tube like an ointment.  You can hold the silicone sheet on with a tegaderm and leave it in place for several weeks at a time.  If the scar is thickening and extending beyond the incision, you may be developing a hypertrophic or keloid scar which will need a more aggressive treatment with the use of a Dermajet to infuse the scar with steroid solution. This will allow the scar to soften, flatten and alleviate the symptoms of discomfort.   It may take several courses of Dermajet infusion in order to fully treat a symptomatic keloid.