ok, I have what is probably a stupid question, but I'm curious: Chemical peels and irritating stuff like retinol, glycolic acid, etc. are supposed to help us look younger by getting our faces all red and dry so that the outer layer peels off. Meanwhile, if you get a sunburn or injury on your face that makes your skin peel, that is horrible for you. Does the sun damage skin at some deeper level while the acids just get rid of the excess on the surface? Any dermos out there who can enlighten?