What is the ruling on using exfoliating cream to remove the traces of acne and scars, which are merely a dark color compared to the rest of the skin?

There is no harm in using creams to treat acne or facial wounds, even if a dark color remains, and this is not considered changing Allah's creation. If the treatment is to remove a defect, then there is no objection to it, by analogy with the Prophet's (peace be upon him) permission for someone whose nose was cut off to wear a nose of gold. However, if it is solely for beautification, then it is forbidden.