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 for severe difficulty breathing, chest pain, fainting, sudden confusion, or signs of a stroke such as facial drooping, arm weakness, or trouble speaking.
These symptoms require emergency care whether or not nail marks are present.
And for anyone, someone who:
is bleeding heavily and it will not stop with firm pressure
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 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 same-day medical advice if new, unexplained splinter hemorrhages occur with fever, chills, night sweats, unusual fatigue, or feeling significantly unwell.
This is particularly important if you have an artificial heart valve, known valve disease, a previous episode of endocarditis, or a recent bloodstream infection.
3
Does any of this apply?
Book an appointment
Arrange a routine appointment if the marks:
Keep returning without a clear injury
Affect several nails
Begin close to the base of the nail
Do not move toward the tip as the nail grows
Occur with nail thickening, pitting, lifting, pain, or swelling
Look more like a widening or irregular dark band
Every sign above is quoted from the sofidex article on Splinter hemorrhages. If you are not sure, err upward — it is always reasonable to be checked.