Could be lichen sclerosis, in which case a steroid cream would help. If you are able, check for any changes or lighter areas of skin in that whole genital area, back to front. Regardless of what it is, go commando, stop using anything like shower gel or soap and use a good emollient to stay moisturised. If you can think of any changes you might have made, foodwise, laundry detergent etc, make a note of that, and also what you have tried already.