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 serious injury is accompanied by heavy bleeding that will not stop or other life-threatening symptoms.
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 for:
a new or changing dark stripe, especially in one nail
pigment spreading from the nail onto nearby skin
rounded fingertips with nails curving downward
persistent swelling, drainage, or soreness around a nail
nail problems when you have diabetes, poor circulation, or reduced immunity
Get same-day medical care if redness or swelling is spreading, pus is collecting, pain is severe, or you have a fever.
These signs may mean an infection needs treatment.
A major crush injury, uncontrolled bleeding, loss of feeling, or a finger or toe that looks bent or poorly supplied with blood needs urgent assessment.
3
Does any of this apply?
Book an appointment
Arrange a routine appointment if a nail change has no clear cause, does not grow out, keeps returning, or is getting worse.
You should also book an appointment if a nail becomes thick, distorted, painful, or detached, or if several nails change together.
Every sign above is quoted from the sofidex article on Nail problems. If you are not sure, err upward — it is always reasonable to be checked.