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 someone in your care:
Is struggling to breathe or making a harsh noise while breathing
Cannot swallow saliva or is drooling because swallowing is impossible
Has blue, grey, or unusually pale lips or skin
Becomes confused, collapses, or is very difficult to wake
Develops rapidly increasing swelling of the tongue, mouth, throat, or neck
And for anyone, someone who:
is struggling to breathe, gasping, choking, or cannot get words out
Other emergency signs, for anyone
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 care for severe one-sided throat pain, a muffled voice, difficulty opening the mouth, significant neck swelling, or worsening symptoms after an initial improvement.
These can occur with an abscess or deeper infection.
Prompt assessment is also appropriate if there are signs of dehydration, a widespread rash with fever, a weakened immune system, or severe symptoms in a young child.
3
Does any of this apply?
Book an appointment
Arrange routine medical follow-up if the sore throat lasts longer than expected, keeps returning, or comes with persistent hoarseness, a neck lump, or ongoing trouble swallowing.
Follow-up is also sensible if prescribed treatment is not helping or causes side effects.
Every sign above is quoted from the sofidex article on Pharyngitis - sore throat. If you are not sure, err upward — it is always reasonable to be checked.