Leave the marks alone, they will fade completely with time.
What you are experiencing is called Post Inflammatory Hyperpigmentation, and it ALWAYS resolves completely, though it can take anywhere from months to a year and a half to fade completely in some cases.
Nothing at all to worry about, it is just the healing process itself and you will be left with beutiful skin. Hyperpigmentation is NOT scarring and is simply a temporary manifestation of the healing process itself.
I swore to the goddesses I wasnt going to answer this inquiry anymore, and yet, here I am, suckered again! This is however, the only statement I will make on this issue, it's very common and has been discussed here many times.