Thank you for your query on Healthcare Magic.
There are two possibilities here:
1. The ear ring may be missed or
2. Your child might have swallowed
But usually if child swallowed, if it is small there will be no symptoms of swallowing if it is entered into esophagus
But by bad luck, if the ear ring enters into air tube, there will be choking
with vigorous coughing, which is unlikely in your child as there are no these symptoms.
But one single X-ray of the chest and abdomen will rule out the possibility of the ingestion of ear ring if it is metallic one.
Consult your Pediatrician
for the examination and for X-ray to know the its presence and the position of the ring.
Hope I have answered your query.