Stains on my foot!?

Today I paid attention to my foot and I realized there’s these brown stains that are really hard to get off they lightened up when I’m ashes them but they won’t completely come off, please give me advice do I have any parasites or anything in my feet!? I’m so paranoid as of right now it literally doesn’t look like anything but like I spilled coffee or stepped in shit ( which I didn’t lol just an example ) but it looks like a typical stain but it’s so hard to come off