I went to my doctor when they once showed up but I don't know if I trust her answer. She told me that if I used bath & body works lotion that its known to change pigment. A few days before they showed up iI remember giving my boyfriend a back massage with the lotion and then changing my tampon. But I've been to a few other doctors since then and each have said/asked me "how long has this been here?", and a when I respond with 'a while' and that 'another doctor said this....' they would respond with "... just as long as you know it's there". and for some reason I was thinking of it again the other day. It doesn't bother me at all. It just seems to be there. But I'm curious as to what it is if all these other people seem to be questioning me about it.