I have heard people use the term "door skin" for both the inside of the door panel and the outside door skin. If it's on the inside just get some leather conditioner. That should clean it up with a little elbow grease. Or try some "Goo Gone." The white, discolored area is prob just the glue from the tape. If it's on the outside of the car try some tar or tree sap remover, some more elbow grease, and then some new wax.
