Is my oranda sick or injured?

I have an Orange & Black Oranda, with an orange wen and white belly,
about 3 inches SL. Have had it for ~20 days. Came home last night to
see two or three white areas on its wen. One speck-size just above
eye; one ~2mm and another sort of like a strip (~1mm wide, maybe 3 or
4 mm long). Larger spot looks very slighty fuzzy.

Did a water change just to be safe. This morning the two smaller
spots are not visible at all; and the larger spot is now circular,
maybe 2 mm in diameter, with the white stuff protruding above rest of
wen by maybe 0.5 mm, and still slighty fuzzy.

Is this a disease? Could it have busted open its wen in some kind of
accident?
Is there some treatment I should be doing to help along its healing?

30 gallon tank, ammonia = 0, nitrites = 0, nitrates hovering around
20-25 ppm, GH ~ 12 dH, KH ~ 3.5 dH, temp ~ 71 oF; RUGF, Whisper
filter, bubble bar and bubble disk.

one other fish, Common GF about same length; a few plants

Thanks for any help!
Dennis