A couple things come to mind that may cause the scales to curl like that. One is your dragon managed to get itself burned to too close to the basking light. He is dehydrated or close to shedding (though there isn't the usual greying of the skin normally associated with sheding in the pictures), mites or some other external parasites. I can't find anything mentioned in the books I have about the scales curling like that.
Unfortunately all I can do is guess, your best bet may be to take him to a qualified reptile vet that is familier with bearded dragons and their diseases.