I'm no vet but when you leave foreign matter in a human's mouth or a dog's mouth you run the risk of infection....and/or the object may rip or tear at the flesh if it moves.
I'd say you must remove it. Try when the dog is sleepy or groggy. Find a good tweezers... and remove.
then keep an eye on the area for a few days...to make sure it's not getting infected.
If you can't do it...take her to the vet.