Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
1
Is any of this happening now?
Call 911
Call emergency services if symptoms after diving include breathing difficulty, chest pain, confusion, weakness, numbness, loss of coordination, or loss of consciousness.
These may suggest decompression illness or another diving emergency rather than isolated ear barotrauma.
A diver with possible decompression illness needs specialist emergency advice.
Other emergency signs, for anyone
Someone who is struggling to breathe, gasping, choking, or cannot get words out
Someone who has chest pain, tightness or pressure lasting more than a few minutes
Someone who has sudden weakness or drooping on one side of the face or body, slurred speech, or sudden confusion
Someone who is unconscious, or cannot be woken
Someone who is bleeding heavily and it will not stop with firm pressure
Someone who has had a seizure that will not stop, or does not wake up afterwards
Someone who has lips or skin that look pale, blue, grey or blotchy
Someone who you believe has taken an overdose or swallowed something poisonous
2
Is any of this happening?
Be seen today
Seek prompt or same-day medical care for:
Sudden or major hearing loss
Severe or continuing vertigo
Blood, pus, or clear fluid coming from the ear
Severe pain that does not settle
A suspected torn eardrum
Symptoms after diving that continue after surfacing
3
Does any of this apply?
Book an appointment
Arrange routine medical assessment if pain, blocked hearing, or fullness is not improving after a flight or dive.
You should also be checked if symptoms repeatedly occur with pressure changes.
The article also says
Do not return underwater to try to relieve symptoms.
Every sign above is quoted from the sofidex article on Ear barotrauma. If you are not sure, err upward — it is always reasonable to be checked.