[yorkieusa]

You could try to sprinkle a little parmesan cheese on it.

"Puppies 12 weeks old will have most of their 28 baby teeth and may have their first 2 to 4 adult front teeth, called the incisors. Over the next three months, your puppy will be getting in all of his adult teeth. Because they are entering an active “teething” stage, they will want to chew. Provide lots of safe chew toys. Begin the first steps toward brushing their teeth by opening their mouths and looking or gently touching their teeth. Make each event positive."

It's possible he could be starting the teething stage. They are all individuals and do develop at their own pace. I don't really know. However, it is possible he just doesn't "like" the food you want him to eat. There are many quality dry foods with small kibble. You may want to try something else. I would still let him have wet food in the meantime. He needs to eat and eat well.