Hi,
I asked because my co-worker had the same thing, had two white spots size of about a quarter or so one on the side and one on the nape. He thought he was going bald, and was soooo worried!
Turned out to be
"Tinea capitis: Ringworm of the scalp
Tinea capitis appears as scalp scaling that is associated with bald spots."
That said, it is only my guess based on your description, and remembering my old friend.
If in fact it is ringworm, I belive Owen had posted about using sesame oil & hydrogen peroxide:
p.s: The good news: my co-worker's went away within a couple of weeks of treatment with a cream (not in touch with - so no way to ask.)[I believe sulphur]