The plastic may or may not show up on an x-ray. Depends on the technique.
The suggestion to drink lots of fluids is a food one.
The chances are it will pass. Do a lot of searching through your poo.
If you feel discomfort head to the ER of a teaching hospital.
Bring along the whistle so they can visualize what went in.
Foreign bodies in stomach may cause serious complications such hemorrhage,obstruction of the intestine,abscess,shock,malnutrition,GI symptoms.It may be an emergency it obstructs and gets lodged near Pyloric sphincter.So have an abdominal X-ray done to locate the object.Take more water.Talk to your doc if you feel uncomfortable suddenly.
Swallowing of a foreign object into stomach may not cause serious problems until it destroys the mucosa of the GI tract that causes serious hemorrhage.Get an abdominal X-ray done in the morning with out taking any food the other night.Tell your Doc about the situation you face.Drugs may be used to promote bowel movements and let the foreign body come out through rectum.Dont ever to vomit out as that may cause the esophagus rupture.Expulsion of object depends on its consistency and size,location and that can be analyzed through X-ray.There may not be serious complications unless it troubles your routine.Check it with your Doc.Keep me updated.