What Causes Brown Marks On My Ankles And Half Feet?

hi there, this is aisha here, i have suddenly got brown marks on my ankles and half feet, i am not happy due to it and want to get rid off from these marks what should i do? I am using fadeoff cream whic is for melasma so is it right to use it or not? What is the way to get rid off these brown marks on feet and from hands too?
Thanks a lot
Nice Regards and waiting for your kind reply in detail
Aisha