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 a person is unconscious, cannot be awakened, is not breathing normally, has repeated seizures, has a serious injury, or may have taken a poison or overdose.
Begin the appropriate first aid while help is coming.
Also seek emergency help if the person wakes but has chest pain, trouble breathing, new weakness, difficulty speaking, severe confusion, a severe headache, or worsening symptoms.
Routine follow-up is for reviewing test results, adjusting ongoing treatment, or discussing return to driving, work, and usual activity after the immediate emergency has been managed.
And for anyone, someone who:
Seek prompt medical advice after any unexplained loss of consciousness, even if recovery seems complete.
Assessment is particularly important after a first episode, an injury, an episode during exercise, or an event accompanied by heart symptoms.
Every sign above is quoted from the sofidex article on Unconsciousness - first aid. If you are not sure, err upward — it is always reasonable to be checked.