Is there an ointment that can make old scars fade?

Hello. I have stitches on my chin from an injury I sustained as a child, and they haven't faded over time. Is there an ointment that could at least make the scar faint, even if it doesn't disappear completely? If possible, I would also like to know how to improve the scar from an appendectomy I had as a child, which is still visible on all skin.