Hey,
Years ago i just noticed that a curved depression was appearing near to the end of my left thumb nail. I don't recall any specific accident or hit, i just remember that it suddenly appeared. However, i didn't really put so much attention to it bc it has never caused me any kind of pain or something (like really, not pain at all).
but now i feel like i need to know that it's nothing bad or any sign of illness or smtn.
That depression is only on my left hand thumb nail, and it's been there for years. My right thumb nail and the rest of my nails are totally find as far i know.