I wondered that too but then I thought about a balloon. Say you have a balloon w/ writing on it- when its blown up, it stretched but the writing is more 'smooth', but when it deflates the writing is all rippled. I don't know if that applies to skin? I've been skin brushing though and that actually helps. I used to be so bothered by stretch marks, but everyone has them, even my 6 ft size 4 model sister does, from growing!