This could be caused by a fungus, and might be helped by a an antifungal ointment or powder such as Tinactin or Undecylenic acid cream.
They are likely a result of dry skin. Use intensive moisturizer, and if you are extremely bothered by them see a dermatologist.
it may be genital warts or some kind of std:(
Probably verruccas, a human papilloma viral infection. They are just warts on the feet. Get a preparation from a drugstore or get them frozen off. Keep feet dry during medication and avoid swimming...
I was wondering the same thing.