It means at least one of two things, and possibly both:
-- You have been walking around barefoot on magic markers.
-- You need to see a podiatrist (foot doctor), an expert, who will examine the area, and then tell you ... based on his expert examination ... either that it's nothing, or else that it's something that should be treated because it doesn't belong there.
DO NOT shop on the internet for health or medical advice. It's possibly the stupidest thing a person can do.
