Hi. Just on the inside of my labia (I mean vagina lips. Is labia correct?), I have a small lump that feels like a blister. It hurts when I touch it. I've had them before. They come and go every now and then. I've had about 5. I have had any sexual contact down there with anyone but myself. So it can't be an std can it? I've used toys down there, but they're been clean. Am worried.