Appendicitis scar - What surgery do I undergo to remove the aftermath? (Photo)

A scar revision surgery is likely to improve your appendectomy scar which is depressed in most cases from scar adhesions to your underlying muscles. See a board certified plastic surgeon - see below link for finding the best.#ScarAdhesions

Thank you for your question and series of photographs.  Based on your description it sounds as if your scar has become tethered to the underlying muscles in your stomach.  In my opinion, the best treatment is to undergo a scar revision to better align the soft tissues underneath the skin to prevent the scar from re-attaching to your abdomen.  This will not remove your scar, but it will prevent the indentation.  Hope that this helps 

Sometimes scars adhere to the underlying fascia over the muscle. A scar revision may be helpful  Best of luck.