I had a lymph node biopsy, so I have a scar on my neck. After the wound had pretty much healed, I began using a silicon scar patch on it. They're sold over the counter (the brand name of mine was Rejuveness), but they're sort of expensive. It's worth it, though!
I tape the clear patch over the scar with medical tape and sleep with it on. My scar has reduced in size, the red color has faded, and the raised tissue has smoothed out. I know that these results aren't just a byproduct of time because I waited over a year before I began using the patch (I didn't know about it before then!), and my scar was pretty gross. Now, it's nice and smooth and not noticeable. I wish I'd have begun using the patch as soon as the wound healed. (You wouldn't want to use it on an open or very tender wound-- the packaging explains when you can start using it.)
You'll probably have to experiment to find a medical tape that doesn't irritate your skin, and, if your scars are very big, you may have to buy two or more patches. Don't use the patch on damp skin and don't apply any creams or salves with it. In short, read all the directions (as I'm sure you'd do anyway).
Let me know how it works out!! Good luck!!