What Causes Small White Bumps On Labia Minora?

I have these tiny white dots in strings on my labia minora, they've been there as long as I can remember, but I'm starting to worry about them. They don't hurt, unless I scratch at them (Which I try to avoid), and they don't look like genital warts, but its been worrying me recently. Any ideas what they are? I am 14, 5 ft 1 inch, and have had my period for 5 years, 3 years regularly. I am a virgin, although I have occasionally masturbated. Thanks!