My 4 month old puppy has stopped eating. She refuses everything and tries to cover it up. The vet can't find any reason for this except maybe it is a reaction
To her puppy shot or Revolution. I have researched and tried everything I could fine. Her past food, new food, dry, canned, hamburger, eggs, you get the picture. She rejects everything. She won't even eat her treats. The only thing she accepts is the Puppy Vitamins. This has been going on for a week and I am
Worried. Help Please! (she is a Lhapso Apso) She is active, running around and playing with her toys. The doctor said she had gained almost a pound but I am at a loss as to how. Any answers would be greatly appreciated.

If she is drinking, sleeping, playing and acting normal I would not be too worried.

I would say she is covering it up to eat later. My guess is that you are trying to feed her too much. I wouldn't make a big deal out of it. Hovering over her and trying to force her to eat will cause issues. She can sense your worrying.

What I would do is take her daily intake divide it into 2 or 3 meals and offer it to her so many hours apart. If she wasn't eating her meals I would not be offering any treats.
I will post the ASPCA guidelines on feeding. ASPCA: Dog Care (http://www.aspca.org/site/PageServer?pagename=pets_dogcare)
For additional tips on pet care.
ASPCA: Animal Poison Control Center: A Poison Safe Home (http://www.aspca.org/site/PageServer?pagename=pro_apcc_poisonsafe)

The other thing you might do is kill off the food bowl entirely. As my old trainer put it, she'd much rather see puppies getting their daily food as rewards for sitting, coming, giving up toys, etc. with anything not earned that way going into interactive food toys (kongs, etc.) That way the dog learns manners, gets a strong bond with the family members, and stays out of trouble because time alone is spent trying to work for food instead of being bored. I know that my dog's appetite picks up when she gets her food in Kongs. Right now she has half a bowl that she has ignored for the last two days, but she will immediately go to work on kongs that I give her.

How long will she go without eating?

DO you have another pet that she could be stealing food from?