She's still teething, and bad breath is quite normal in teething puppies.
Check all her teeth & gums to make sure none are impacted (the baby tooth hasn't been pushed out by the adult tooth) or for redness & gum swelling. If all looks OK & she's chewing normally, it's probably no big deal.
If you're not sure, or you have a hard time checking, have your vet take a quick look-see in her mouth. Sometimes a baby tooth gets impacted & will get infected.
Cooper The WonderDog
Daphne The Destructo-Rott