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 there is:
Trouble breathing, severe wheezing, or blue or grey lips
Rapid swelling of the lips, tongue, face, or throat
Collapse, a seizure, confusion, or difficulty waking
Sudden weakness or severe chest pain after swallowing bleach
Severe eye pain or sudden loss of vision
Vomiting blood or severe chest or abdominal pain
And for anyone, someone who:
you believe has taken an overdose or swallowed something poisonous
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
2
Is any of this happening?
Be seen today
Contact a poison centre immediately after any swallowed hair bleach, a significant inhalation, or an eye exposure.
Do this even if symptoms are mild or have not yet appeared.
Continue eye rinsing while help is arranged.
Prompt medical assessment is also appropriate for persistent vomiting, drooling, difficulty swallowing, blistering burns, worsening cough, or reduced vision.
3
Does any of this apply?
Book an appointment
Arrange routine follow-up if a rash, cough, wheeze, or eye irritation is not settling as expected.
Repeated symptoms during hairdressing work should also be assessed because they may indicate occupational asthma or contact dermatitis.
Every sign above is quoted from the sofidex article on Hair bleach poisoning. If you are not sure, err upward — it is always reasonable to be checked.