U R overthinking!
4 me VA started with repeated urine infection-type symptoms: feeling like the need2P continually. My GP recognised the symptoms by reading my records, recommended treatment over the phone and hey presto! Once I began inserting Ovestin into the vagina at night as well as taking 2 Nurofen 3 times a day to ease the nip as the urine flow stopped, symptoms improved. I also get a feeling across the area under my belly button, kind of 'tight' which is a warning.
If someone uses too much preparation some will wipe off, which may be flaky. Some will stain the panties but that's OK! What goes up ;-). When my outer labia itch I either apply 'savlon', 'KY Jelly' or 'ovestin' where it itches when necessary, as well as internally at night. If possible, put a thin layer of your choice and lay naked on your bed, to allow it to soak in. Keeping the whole area moist will stop the itching. Once symptoms are under control, don't stop using treatment.
Yep the sensations can 'move' around as different areas become dry, thin and itchy. There R a lot of nerve endings around that area!