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 immediately if the person cannot breathe, speak, or cough effectively, becomes confused, turns blue or grey, collapses, or does not recover normal breathing after the object comes out.
Emergency help is also needed for severe chest or abdominal pain, coughing up blood, repeated vomiting, fainting, or worsening breathing difficulty.
Arrange prompt medical assessment after any use of abdominal thrusts, even when the person appears to have recovered.
And for anyone, someone who:
This is routine follow-up to check for hidden injury or a remaining piece of the object.
The article also says
Contact your healthcare team again if coughing, wheezing, painful swallowing, fever, chest discomfort, or abdominal pain develops or continues after the initial assessment.
Every sign above is quoted from the sofidex article on Abdominal thrusts. If you are not sure, err upward — it is always reasonable to be checked.