Do you shave? It could possibly be razor burn if you do. Also, you can just get
acne around your genitals if you don't wash well enough. A lot of women gen genital acne because they don't realize how thuroughly you have to clean yourself.
Don't use acne cremes or face washes down there though, because you could give yourself severe irritation. Take a warm washcloth with body wash and clean the area gently.