Is he acting strangely? Lethargic? Is his appetite normal? 12 days isn't unheard of for some dragons. Is he an adult?
You may want to try offering drops of water on his nose for him to lick up. Keeping him
hydrated will help him clear his system if he's blocked up. You can also try a couple drops of olive oil or a little bit of pumpkin, prune, or applesauce baby food which is known to help as well.
If he's acting OK otherwise I wouldn't worry about it too much but try to make sure he's getting enough
hydration.
If you want to post details about his enclosure temperatures and lighting etc I can review it and make sure his setup is optimal as well. Heat and lighting have a direct effect on their digestion and overall health.