Use Retin-A exactly as your doctor has prescribed it for you. Follow all directions on your prescription label. Do not use this medicine in larger or smaller amounts or for longer than recommended. Do not take by mouth. Retin-A is for use only on the skin.
Definition of wall for English Language Learners : a structure of brick, stone, etc., that surrounds an area or separates one area from another : the structure that forms the side of a room or building
a wall-like, enclosing part, thing, mass, etc.: a wall of fire; a wall of troops. 5. an embankment to prevent flooding, as a levee or sea wall. 6. the outermost film or layer of structural material protecting, surrounding, and defining the physical limits of an object: the wall of a blood cell.