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 now if a sting is followed by:
Trouble breathing, wheezing, or tongue or throat swelling
Collapse, fainting, confusion or a seizure
Chest pain or an abnormal heartbeat
Severe pain affecting several parts of the body
Repeated vomiting, heavy sweating or marked agitation
Unresponsiveness or abnormal breathing
Suspected contact with a dangerous box jellyfish
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
Get urgent medical advice for a sting to the eye, mouth or throat; severe pain that is not easing; a large area of affected skin; or symptoms that begin to spread beyond the sting site.
A young child with an extensive sting should also be assessed promptly.
3
Does any of this apply?
Book an appointment
Arrange routine follow-up if the rash keeps returning, marks are not improving, itching remains difficult to control, or you develop possible infection signs such as increasing redness, warmth, pus or fever.
Every sign above is quoted from the sofidex article on Jellyfish stings. If you are not sure, err upward — it is always reasonable to be checked.