I've found that apple cider vinegar mixed with equal parts water for a 1:1 solution and applied to scars morning and evening is quite effective. Using this in combination with using an egg white mask (one egg white mixed with a teaspoon of lemon juice) seems to fade the marks dramatically. Give it a try and see if it works for you.
I found this information at acne.org. Here's the link:
I have found that it is helpful to apply a moisturizer either in the morning or evening as it can make your skin quite dry.
I came across some pictures of this one woman whose skin now looks really nice as a result of using the ACV and egg white mask. Here's a link to her photo page: