Why not skip the trauma and inoculate the cuticle with fungus directly?

I try to remember to put a drop of rubbing alcohol on the edges of my rough, thickened toenail every day or two. As long as I remember, new healthy nail gradually comes up from the base. When I forget, the thickened part spreads back down. One of these years, I'll remember long enough for the ugly bit to get pushed off the top and cut off, and it'll be back to normal.

I think mine started from an injury too.