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
Seek emergency care if you have:
Difficulty breathing
Difficulty swallowing saliva or new drooling
Rapidly increasing swelling under the tongue or in the neck
Severe weakness, confusion, or fainting
These symptoms can mean that swelling or infection is affecting deeper tissues or the airway.
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
Arrange urgent, same-day medical assessment for painful gland swelling with fever, pus, worsening redness, or feeling seriously unwell.
Prompt assessment is also important if you cannot drink enough, have a weakened immune system, or the swelling is getting worse quickly.
And for anyone, someone who:
has a fever with a stiff neck, a rash that does not fade under pressure, or severe headache
has a wound that is hot, spreading red, or leaking pus
3
Does any of this apply?
Book an appointment
Routine follow-up is appropriate for swelling that repeatedly appears during meals, ongoing dry mouth, or infections that keep returning.
Get reviewed if symptoms are not beginning to improve after treatment or if a lump remains after the pain and inflammation have settled.
The article also says
If mumps may be possible, contact the healthcare service before arriving.
This allows staff to reduce the chance of exposing other people.
Every sign above is quoted from the sofidex article on Salivary gland infections. If you are not sure, err upward — it is always reasonable to be checked.