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 you or a child has:
Severe trouble breathing or pauses in breathing
High-pitched or harsh breathing sounds
Blue, grey, or very pale lips or skin
Inability to swallow saliva with breathing difficulty
Collapse, confusion, or difficulty waking
Rapidly worsening neck or throat swelling
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
Seek urgent same-day medical assessment for fever with neck stiffness, painful swallowing, drooling, a muffled voice, refusal of liquids, or an unusual fixed head position.
These symptoms have several possible causes, but a deep neck infection needs to be ruled out.
After treatment, contact the hospital team or seek prompt reassessment if fever returns, pain or swelling worsens, swallowing becomes harder, medicines cannot be kept down, or recovery is not progressing as expected.
3
Does any of this apply?
Book an appointment
Routine follow-up should still be attended even when symptoms are improving.
The article also says
Keep the person as calm as possible while waiting for help.
Do not force food, drink, or medicine if swallowing or breathing is difficult.
Do not press on the neck or try to examine deep inside the throat.
Every sign above is quoted from the sofidex article on Retropharyngeal abscess. If you are not sure, err upward — it is always reasonable to be checked.