I don't think there is much you can do.
You can try to feel if the earing is lodged in it's crop first thing in the morning. If it is as large as you suggest then it should be quite obvious. If it is still in the crop then crop surgery to remove it is an option, preferably carried out by a vet.
If the earing has moved down to the gizzard then I doubt a vet would try and retrieve it unless they were very experienced in chicken surgery. It certainly isn't on the home operation list.
On the bright side chickens can and do live having swallowed all sorts of unhealthy objects.
Keep checking the poop and cross your fingers.
Oh, welcome to BYC by the way.