There are things like Mederma, various oils and creams. There are also laser surgery options for drastic cases. It's probably best to see a skin doctor. That said, naturally it's going to lighten up a bit over the years, though third degree burns will tend to leave quite a scar indefinitely. Scars are cool on girls, no need to be so self-conscious about it.
depends on how bad the burn was some burns go away with time others dont but the ones that don't tend to be the ones that are caused by extreme burns like putting your hand in a fire for a few seconds quick touches to an iron might just be a lesser burn that will heal up over time i burned my elbow on a burner once it took a few months for the scar to go away