Explain exactly what he is doing? Is he chewing on your hair? Is he pulling out your hair? Do you mean that he is grabbing the hair on your head or is he grabbing loose hairs he finds on the floor? When is he doing this? How often does he do this?
If he is grabbing the hair on your head, how is this happening? Is it when you are sitting down or lying down? (there's no way a pug could do this if you were standing up). Do you mean he is actually pulling out your hair and eating it? Do you let him do this? What do you do to try to prevent it?
How old is your pug? How long has he done this behavior? Is he neutered? Does he have a tendency to chew on and eat other inedible objects?
What type, brand, of food do you feed him? How often does he eat per day? How much (how many cups) do you feed him per feeding? Does he eat his food when you feed him? Is he a good eater or a finicky eater?
Is your pug healthy? Does he have any medical conditions? When was his last veterinarian check up?
Thanks for answering these, they will help me to answer your question.