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 your lips swell suddenly along with tongue or throat swelling, breathing difficulty, faintness, or trouble swallowing.
These can be signs of a severe allergic reaction.
And for anyone, someone who:
has lips or skin that look pale, blue, grey or blotchy
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 you believe has taken an overdose or swallowed something poisonous
2
Is any of this happening?
Be seen today
Seek same-day medical care for spreading redness, increasing warmth or pain, pus, or fever.
These features may indicate an infection.
Urgent assessment is also appropriate for severe lip peeling or blistering with sores in the mouth, eyes, or genital area, especially after starting a medicine.
3
Does any of this apply?
Book an appointment
Book a routine appointment if your lips:
Do not improve after about two weeks of gentle care
Keep becoming chapped without a clear trigger
Have painful cracks at the corners that do not heal
Develop repeated blisters, crusting, or bleeding
Have one persistent rough, thickened, discoloured, or ulcerated area
Make eating, drinking, or opening your mouth difficult
Arrange earlier advice if you have a weakened immune system or have recently started a medicine that may be affecting your lips.
Do not stop a prescribed medicine without discussing it with the prescriber.
Every sign above is quoted from the sofidex article on Chapped lips. If you are not sure, err upward — it is always reasonable to be checked.