Quiet Man's corn started out just like what you described, and that was a year ago, He had an intermittent limp on pavement, tiny black dot, etc. Mt vet also thought a foreign object had gotten in there (he doesn't have experience with corns). A year later it's worse than ever, and the only thing that seems to help is the Therapaw which has been a godsend. If it is a corn, it will grow slowly and come to the surface, you can pick it out, hull it out, pumice it down, put duct tape on it to soften it, but nothing seems to make it go away forever I'm afraid