Hi. White patches could be a sign of Lichen Sclerosus, itching and soreness is another symptom. You def need to see your GP to get this diagnosed (or not!). If it is LS then steroid cream will be prescribed.
Whilst waiting on your Dr appt, join the Lichen Sclerosus UK Support Group for Women on FB. It's a fantastic supportive group and you'll pick up some great tips for soothing the area whilst waiting for a diagnosis.
Antihistamines can be helpful for the itching.
Suzie