How can I get rid of hyperpigmentation left by a year old curling iron related burn on the arm? (photo)

Hi,I burned my arm in two spots, about a year ago while curling my hair with a titanium wand. The burn left two brownish scars one a nickel, the other a quarter sized. Although the skin has totally healed (no bumps), the scars although slightly lighter have not disappeared. The scars are unsightly &I feel self-conscious baring my arm, I have tried silicon sheets & natural remedies to no avail. Is there a way I can get the hyperpigmentation to safely disappear? Or are the dark spots here to stay.