Fake tan will make it stand out more. A little while ago now, I went to the summer ball at uni, and was wearing the ball dress that I still had from my year 11 ball. But it was backless and I had a spinal op since I had worn the dress before and didnt really like the scar. I had been using bio oil etc on it, which had helped a bit a decided to try fake tan on it. It didn't work at all. Best way to describe it is if you draw on a piece of paper with wax crayon and and then paint over it the paint won't take on the parts with the wax on. If you know what I mean that was what it was like, because the scar is almost like a different type of skin the fake tan wouldn't 'take' on it. So in the end it made it more obvious as the rest of my back was browner and the scar was still white.
Anyway, after my rather confusing explanation, I very much doubt that fake tan will help with your scars. Like Erana has said though, try not to worry about them.