My puppy is a 5 month old female maltese, she has not pooped in several days, like 3. she is acting fine but I don't want to have a problem. Is there something I can give her to get her going again?

You could try and feed her about 1/4 cup of yogurt, any flavor works. If she doesn't have a bowel movement within 15-20 minutes, then you're going to have to take her into the vet. I'm surprised you haven't already taken her in. She is probably uncomfortable. Animals can survive quite a few days in pain before you notice it.

Has she been throwing up? Eating, drinking? If so, then there might not be a blockage. If she isn't eating or drinking, then I would suspect a blockage.

Either way, you need to contact your vet.

You say she is acting 'fine', so I would need to make sure she isn't going somewhere that you are unaware of. Even if a dog is completely housebroken, it is still possible that something has caused them to feel the need to break training. It is going to be in an area that she seldom ventures into otherwise.

Then, finding nothing, you may want to consider a trip to the vet's, where I would hope your dog wasn't just given an enema and watched. An abdominal X-ray is in order to rule out an obstruction. Then, if it seems to be simple constipation, an enema would be in order, and a change of diet in order to prevent further episodes like this.

I had a client once who was positive that her dog was not eating. Well, it wasn't, at least not at home. Come to find out, he was helping himself to the neighbor's dog's food down the street.