Hey, i've used mederma. It's very expensive. I have scars all over both arms from the rashes I get from the sun. Not only is it very expensive, but the tube doesn't last very long (i was buying the largest tube) and you have to apply it several times a day. And for a long time. I used it on my arms for about 2 months, and only after 2 months did I start seeing a change in the appearance of my scars. And it wasn't much of a change.
I got discouraged and stopped using it. Though I think if I had continued to use it, it may have made a difference.
There is a money back guarantee, so give it a try. But as a warning, it takes a long time to work.
~szeeba~