When mine turned black and brown, I felt terrible when I went to the pool or spa. Felt I needed a big sign saying "I don't have a fungal infection"!! Didn't stop me though and nobody said anything which was a relief. I thought of using nail polish, but it would not have hidden the splits and the thickening, might have made it even more noticeable. Even now (only one slightly damaged one left - nearly 4 years after all non tablet treatment) my toenails still get discoloured if I apply varnish regularly, they need a break.