Dry and sore vagina

Patient: I am 14 years old, and recently for a few days, I have noticed my vagina feeling really dry, and a small red piece of skin hanging off the lip. This has happened before, but it went away after about a week when I washed myself thoroughly, especially my vaginal area. It also feels quite sore. Btw, I have never had sex so it can’t be and std. i am too embarrassed to tell anyone about this, especially my mum. Please help!