I also have dark spots on my toes but its due to the fact that i have used a corn remover product named Freezone and it has left a red and black spot on the top of my toe and i dont know how to get rid of it
the acids from the corn remover has damaged your skin. it may never be the same.
you can try to help it by consuming 1000 mg vit C daily and applying vit E oil to it daily.