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 a baby develops breathing difficulty, becomes unusually unresponsive, or has blue or grey colouring of the lips, tongue, or skin.
These symptoms are not caused by a stork bite, even if the birthmark also looks darker at the time.
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 prompt medical advice if the area becomes painful, hot, swollen, or begins leaking fluid, especially if there is fever.
These are not typical features of a stork bite and may indicate an unrelated skin problem.
Seek urgent help if bleeding does not stop after firm, continuous pressure.
And for anyone, someone who:
has a wound that is hot, spreading red, or leaking pus
3
Does any of this apply?
Book an appointment
It can usually be discussed during a routine newborn examination or regular health visit.
Arrange a routine medical review if:
You are unsure whether the mark is a stork bite
It becomes raised, lumpy, darker, or sharply outlined
It grows rather than fading as the child grows
It remains prominent and is causing distress
A facial mark affects one side or extends around an eye
The skin becomes repeatedly irritated or starts to break down
The article also says
A stork bite itself is not an emergency.
Every sign above is quoted from the sofidex article on Stork bite. If you are not sure, err upward — it is always reasonable to be checked.