It may well be a case of costia which leaves a whitish haze over the fish if it was whitespot you would see the entire fish so afflicted also the fishes fins would be clamped,
Here at the moment at least we are only looking at the head being a problem area .
A good over the counter anti parasite treatment should clear this up
Has the goldfish any symptoms of clamping that has since taken place from when you posted, to make me change my mind and plumb for whitespot ?
rgrds
Dave