I can't answer your question directly, but I do have a thought on it based on one of my banded friends. If you tan often enough, the scars will show up differently than your skin so they stand out more. Not sure if the y're darker or lighter, I just remember seeing them more obviously after she went tanning for a while.
I know that's not what you were asking, but if you can find a way to get a more even tan or something, that might be worth asking about be fore you go tanning.