You could do chemical peels at your dermatologists office. They recommend you do a few - one a month - getting stronger each time so that its takes the top layer of skin off.

Or, you could try renova or aha cream.

Or, you could try your drugstore as they have - by the Neosporin section - creams that are specifically for scars (from post surgery scarring, acne etc) I haven't tried them but you could check them out.