Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Call emergency services for heavy bleeding or if your baby becomes very pale, difficult to wake, or has trouble breathing.
These are not expected effects of nail care.
Seek urgent medical care if bleeding continues despite steady pressure, the cut appears deep, or part of the nail has been torn away.
A rectal temperature of 38°C or higher in a baby younger than 3 months needs prompt medical assessment, whether or not it follows nail care.
Contact your healthcare team during routine hours if a cut is not healing, or if you notice increasing redness, swelling, warmth, tenderness, pus-like fluid, or an ingrown nail.
Also ask for advice if you cannot safely distinguish the nail from the skin.
Every sign above is quoted from the sofidex article on Nail care for newborns. If you are not sure, err upward — it is always reasonable to be checked.