I developed a large scar after my strip hair transplant, why?

Scars like this are usually the result of an over aggressive surgeon who took out too much width in the strip and had too much wound tension at the time he closed the wound. Alternatively, a very elastic collagen present in some people can produce stretching of the wound and that would reflect your genetic make-up with regard to the way you heal such scars. The best treatment for this is Scalp Micropigmentation (see here:https://ift.tt/2uw2y1f). Sometimes, with scalp exercises, you can loosen up the scalp enough to try to get the scar removed and at that time the surgeon would perform a trichophytic closure which will help get a better scar, but unless your scalp is loose enough, a surgery will not work.