Breast disease? HELP !!!?

hi im a 15 year old girl and itz like I have a black crust growin on the side of both my nipples like from the center. It doesn't realy hurt when I touch it and itz juz there. Itz been there for atleast 2 yearz already but I haven't told anybody. Den about a week ago, da crust thingy from my right nipple fell off. It doesn't hurt or anything and itz just gone. I dnt know wat it iz and I'm scared to tell anybody so please if u kud give me an idea of wat it is. Also there are like white spots on my arreola. And my right breast is bigger den my left. I'm realy scared and I dnt know wat it is. I'm a virgin also. And I have like dented nipples like in the very middle but I read dat that's where the milk is suppose to come out but idk. HELP ?