I have small white bumps on my chest, also. Alas, I suspect you are correct in your description of them as scar tissue. I think its sun damage.
I was reckless in the sun when i was younger. Fortunately, I saw the future in a relative who had big white spots on her forearms. Now I am a vampire, hiding from the sun.
Sorry! I wish I could tell you it will go away, but if you're not careful, you could get lizard skin.