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 you have a new non-blanching rash and are very unwell, especially with fever, confusion, unusual sleepiness, a stiff neck, breathing difficulty, fainting, or rapidly spreading spots.
Emergency care is also appropriate for:
Bleeding that will not stop with firm pressure
Vomiting blood or passing a large amount of blood
Severe headache, vomiting, confusion, or weakness after a head injury
Extensive bruising after a serious injury
Signs of severe blood loss, such as fainting or marked breathlessness
And for anyone, someone who:
is bleeding heavily and it will not stop with firm pressure
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 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
Do not wait for every symptom to appear.
Seek same-day medical advice for new, unexplained, or widespread pinpoint spots, even if you otherwise feel well.
Get prompt advice if marks occur with repeated nosebleeds, bleeding gums, blood in urine or stool, unusually heavy periods, or large unexplained bruises.
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
Book a routine appointment if bruising keeps returning, becomes more frequent, or takes longer than expected to fade.
Mention any family history of unusual bleeding.
And for anyone, someone who:
has noticed a lump, a mole that has changed, or unexplained weight loss
The article also says
If you take medicine that affects clotting, ask for advice about unexpected or increasing bruising.
Do not stop prescribed medicine on your own.
Every sign above is quoted from the sofidex article on Bleeding into the skin. If you are not sure, err upward — it is always reasonable to be checked.