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 now if the person:
Begin cardiopulmonary resuscitation if they are not breathing normally and follow the emergency dispatcher’s instructions.
And for anyone, someone who:
Contact a poison centre immediately if hair tonic has been swallowed, even if the person feels well.
In the United States, Poison Help is available at 1-800-222-1222 .
Elsewhere, contact your local poison information service or urgent medical service.
New vision problems, worsening confusion, breathing difficulty or repeated vomiting are not routine follow-up issues and need urgent reassessment.
Routine follow-up may be appropriate after discharge if symptoms are improving but have not fully settled, or if the care team recommends repeat vision, kidney or neurological checks.
The article also says
Place an unconscious but breathing person on their side if you can do so safely.
Do not put anything in their mouth.
Every sign above is quoted from the sofidex article on Hair tonic poisoning. If you are not sure, err upward — it is always reasonable to be checked.