Does she feel tight in her chest at all? My sister swallowed money as a child and had to get an dray to make sure it wasn't in her windpipe.

I would be getting her to poo on the potty and sifting through to see if it cones out. If not I would consider getting further tests, because the decomposition of metal in her body could be harmful over time. (I heard about a ottos girl who got very sick from a coin swallowed as a baby).