Hello I m from india there are black lines growing on my right hand finger nails intially it ws on only on my thumb nail now it started growing on othere suggest me what shold I do I m worried
I had light black line with 1.5mm thick vertical
Suddenly I got a black thin vertical line on my hand on the thumb finger. Even though I cut my nail, a new nail is also growing with that black line. What does that mean?