A human face is something that needs to be perfect on the photo when it is for commercial use. Photo retouching service is there to fix every flaw of a photo and make it perfect. It works on spot removing, skin brightening, make-up fixing, teeth whitening, wrinkle eliminating, unwanted object removing, old photo restoring, etc. and many other services and included in photo retouching.
Photo retouching services include many things related to photo editing. It focuses on portrait photographs. Because portrait pictures show every detail of a human and especially on the face, if you have a single flaw in your portrait photo, it will be a failure, and that is not attractive at all.