There are MANY possible causes, so see a dermatologist. But two likely possibilities are allergies to something you touched or irritation (e. g. to cleaning fluids).
It could be due to contact with a poisonous or caustic irritant, or something to which you are allergic. The good news is that most "contact dermatitis" is treatable.
It is possible that you have a hereditary disease called pulmonia, a light dermal scarring spread from family members through time. A topical creme may be of effect.
