Does anyone know what this is on my DD's nail? Image included

[Amuseaboosh]

My DD showed me this yesterday. We're trying to work out if it's showing up because of some sort of vitamin deficiency or a collection of blood under her nail?

Any ideas, please?

OP you daughter should go to a doctor and ask for a referral to dermatology. It could be a form of skin cancer or it could be absolutely nothing. Best get it checked without delay.

Has she injured the nail in any way?