Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Call emergency services now if the person cannot breathe, speak, or cough effectively; develops blue or grey lips; collapses; or appears to have a completely blocked airway.
Follow the emergency operator's instructions and use age-appropriate choking first aid if you know how.
Go to an emergency department immediately after swallowing:
Immediate assessment is also needed for drooling or inability to swallow saliva, breathing difficulty, severe neck or chest pain, repeated vomiting, blood in vomit or stool, severe or worsening abdominal pain, fever, or a hard or swollen abdomen.
And for anyone, someone who:
Seek urgent same-day medical advice if a young child may have swallowed an object, the object is unknown, or you are unsure whether it was a coin or battery.
This also applies if the person has esophageal narrowing, a swallowing disorder, or previous digestive tract surgery.
Get reviewed sooner if new pain, vomiting, fever, bleeding, swallowing difficulty, or breathing symptoms develop.
Once a clinician confirms that the object is low risk and suitable for observation, follow the planned follow-up.
Every sign above is quoted from the sofidex article on Foreign object - swallowed. If you are not sure, err upward — it is always reasonable to be checked.