Mouthing, chewing and biting objects is natural and a part of your puppy’s natural exploration of his environment.
I like Deanna’s answer.
Since he is chewing your face… probably other thing also so here is a way to deal with it.
This exploratory behavior can however, result in the damage of household items and possibly result in injury to your pet. It is inappropriate to punish your puppy for destroying items unless you “catch them in the act.”
It is inappropriate because punishment after the fact to diminish bad behavior is ineffective. Your dog cannot make the connection between your reprimand and its chewing behavior unless punishment is given during or immediately after chewing. Yelling and hitting the pup with a rolled-up newspaper is not only a unkind assault against your puppy, it actually teaches him under stress you are a person to avoid.
If you come home to find your $200 shoes a pile of scrap leather the only thing you should immediately do is clean it up. Ignore the puppy and consider what you must do before your home is reduced to rubble.
Now lets suppose you see the rascal chewing the shoe or your favorite chair corner right in front of you! Get ready....Your goal is to startle your pet and distract him from his destruction. It is OK to say a snappy “NO!” So do it! Say it snappy like 3-4 times. No..No.Nooooooo!. NO! This will focus him on your displeasure and suddenly your displeasure is his too.
So the procedure of correcting your puppy in the act is
1) With a firm and sharp command say, “NO!” “NO!” “NO!” – it should be unpleasant enough he would not wish to experience it again. Don’t worry it is not harmful to say NO to your dog when he is appropriate.
2) Take the item away from the puppy.
3) Move the puppy to a new location.
4) Immediately following relocation.
5) Give the puppy an acceptable toy or bone.
6) Now offer immediate and enthusiastic praise and a pat.
I always move the puppy to a new but SUPERVISED location even if it is but a few meters away from the area of the digressed behavior. The main reasons for relocating the curious pup are to emphasize the area and objectionable behavior and to prevent an immediate reoccurrence of it by making it more inaccessible. The act of removing a dog from an interesting situation can be considered aversive to the curious puppy, so is important you offer him a new toy or he may redirect his anxiety and find other forms of reinforcement. <img src="/ubbthreads/images/graemlins/wink.gif" alt="" />
Remember the easiest way to train a dog is to not allow the mistake to happen to begin with.
Have fun <img src="/ubbthreads/images/graemlins/laugh.gif" alt="" />
A dog teaches a boy fidelity, perseverance, and to turn around three times before lying down. - Robert Benchley
In order to really enjoy a dog, one doesn't merely try to train him to be semi-human. The point of it is to open oneself to the possibility of becoming partly a dog. - Edward Hoagland