Okay, I am squinting pretty hard at those pics.. and what I think I'm seeing is pinkish skin under clear scales around the betta's head area, with white scales elsewhere on the fish...
If he's not acting ill at all, I would say this is his colouring (I could be wrong, since the pics aren't very clear and you haven't actually described anything..) -- if he had ammonia burns bad enough to take all the scales off his head like that, he'd be one hella sick looking fish by now.
Some of the symptoms of ammonia poisoning can be:
Loss of appetite
Hovering at the bottom of the tank
Gasping at the surface (not just the normal 'sipping' the air for breath, as bettas do)
Red streaks or inflammation in the gills and skin
Inflamed eyes or anus
Keep in mind though that new bettas often go off their food and seem to 'sulk' for a few days anyway, while they adjust to the new water chemistry - especially if they aren't acclimated to it slowly.