I'm 24 I've always had inverted nipples, they tend to come back out when I get cold or aroused but at normal times they have always been this way this have never caused me a problem but over the last few years both nipples develop a yellow crust in the nipple this flakes away when I rub it but happens daily, just wondering if this is something I should be worried about I've checked my breasts and there is no lumps and they don't pimple in anywhere, what could be causing this?