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 the person:
Has difficulty breathing or is turning blue or grey
Collapses, cannot be awakened, or has a seizure
Cannot swallow or is drooling heavily
Has severe choking or rapidly worsening symptoms
Do not wait for poison-centre advice before calling emergency services when breathing or consciousness is affected.
If there is an immediate danger of further self-harm, call emergency services or a local crisis service and stay with the person if it is safe to do so.
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
Seek urgent medical assessment for:
Persistent coughing, choking, or wheezing
Repeated vomiting or inability to keep fluids down
Increasing sleepiness, confusion, or unusual behaviour
Significant mouth or throat pain
Symptoms after swallowing medicated, pet, concentrated, or professional shampoo
Any exposure involving a very young child or someone with swallowing problems
Eye pain or vision changes that continue after rinsing
Intentional swallowing also needs urgent help.
The article also says
Contact a poison information service after shampoo is swallowed, especially if the amount or product is uncertain.
This is appropriate even when there are no symptoms.
Keep the container nearby when calling.
Every sign above is quoted from the sofidex article on Shampoo - swallowing. If you are not sure, err upward — it is always reasonable to be checked.