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 help for symptoms that could mean a sudden loss of blood flow or a rapidly spreading infection.
These include:
Sudden severe chest pain, trouble breathing, or heavy sweating
New facial drooping, arm weakness, speech difficulty, or confusion
A limb that suddenly becomes very painful, pale, cold, numb, or weak
Severe pain that is much worse than the visible injury
Rapid swelling, spreading redness, purple or black skin, or new blisters
Fever with confusion, faintness, a very fast heartbeat, or difficulty staying awake
Severe and persistent abdominal pain, especially with vomiting or a rigid abdomen
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
Contact a healthcare service promptly for a wound that is becoming darker, more painful, swollen, or foul-smelling.
Pus, fever, spreading redness, or a wound that is not healing also needs timely assessment.
3
Does any of this apply?
Book an appointment
Arrange routine follow-up for ongoing joint or bone pain, reduced movement, or a scan report that mentions necrosis.
If you already have diagnosed necrosis, report a new change in pain, skin colour, wound drainage, or function rather than waiting for the next planned visit.
Every sign above is quoted from the sofidex article on Necrosis. If you are not sure, err upward — it is always reasonable to be checked.