Hello, i was about 6 years old and i went to the beach with my family ,, stayed in the sea for a long while ,, maybe 6 hours everyday for about 6 days ,, and then my right arm got burned and turned to dark brown afterwards ,, i still have this dark brown area on my right arm im 18 years now ,, i went to a doctor and his diagnosis was pigmented hairy nevus and it has nothing to do with the sun and the sea maybe it was just timing ,, it s a bit hairy but not that hairy it s also a large one extending from my shoulders to half of my left arm ,, i wasn t born with any birthmarks or any nevus... can you help me out with this case ,,