My left labia minora is swollen and tender, and there is a very large dark sore near the vaginal opening. When I first saw it I thought of a scab, because it sort of looks like that. There are also smaller, open sores on both labia. It is painful to urinate, to wipe, and to sit in certain positions. I am 17 and have never had sex. I really have no idea what this could be, and it's freaking me out a little. Please help.