1990 D Lincoln Cent, Misplaced Mint Mark

If it was a sneeze that was later cleaned, the stain would verify you cannot just clean away stains. Never never clean your coins! Many a coin have been ruined value wise by cleaning.

All that said, what you have here is not a misplaced mintmark. On cents, the last mintmark placement by hand was 1989. Only quarters had their mintmarks placed by hand in 1990, and your coin was not mistaken for a quarter, sorry. Your coin has a broken plating bubble in which the next stage is zinc rot. Spend it while you still can!