My didnt develop?

Between the ages of 13 and 16 i weighted about 6 stone,severly underweight,i went through phases of not eating and my s havent developed,i i have the same colour as my skin and when i say they didnt develop i dont mean i have small i mean i have nothing just an inverted nipple,my periods didnt start till i was 16 and started gaining weight but at that time i was still 7 stone,now i am 23 and its ruined my life,i have never shared this with anybody ,do you think there is anything i can do to start the development of my s?