I have a white line on my nail and i suspect that it might be melanoma?

In the same direction as your finger going the whole way like a stripe or a horizontal one? White lines are usually trauma, and will grow out over time. Take a picture and track over a few months if you want. Melanomas are usually black. An image here would be very helpful.

Melanomas can occur under the finger or toe nails as a brown or black lesion. A white line on nail is most likely from an injury to the nail matrix. This is called LEUKONYCHIA and could also be from an allergic reaction to nail polish, gloss, hardener or remover. Chemicals from the removal of acrylic or gel nails can cause this whitening.