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 if tongue swelling is sudden or if there is:
Difficulty breathing, gasping, or worsening noisy breathing
An inability to swallow saliva
Swelling of the lips, face, or throat
Faintness, widespread hives, or other signs of a severe allergic reaction
Blue, grey, or unusually pale lips or skin
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
Do not wait for a routine appointment when breathing is affected.
Rapid swelling can progress quickly.
Seek prompt medical assessment if an enlarged tongue is accompanied by choking, repeated coughing during meals, poor feeding, dehydration, unexplained weight loss, repeated chest infections, or pauses in breathing during sleep.
3
Does any of this apply?
Book an appointment
Arrange routine follow-up for a tongue that appears persistently large, is gradually enlarging, rests outside the mouth, or causes speech, dental, swallowing, or sleep problems.
New tongue enlargement in an adult should also be assessed, even when it is painless.
Every sign above is quoted from the sofidex article on Macroglossia. If you are not sure, err upward — it is always reasonable to be checked.