Never say never, it can take a long time for objects to pass through a dog, with the risk of leaking ink too, I would proberbly say not to take any chances.
Generally when a dog eats something that the body can not break down it will sit in the stomach or bowel and either cause constipation, and eventually pass through the motions or a dog will continually vomit bile until the object is brought back up it can take days until the body is forced to eject it, so she may not show any signs yet.
I'm just a little worried about the ink inside the pen bit, (am I understanding that right, it is the inside of the pen that is missing) could you call your vet to ask whether this would be dangerous to your dog if it leaks into her body?
Have a check under the sofa, chairs etc, to see if it has rolled anywhere first though.
P.S. you would be surprised at what dogs can eat

Hopefully she will be ok, but please just check that fact first.