What Do Dark Scars On Chest Indicate?

age - 17
height - 5'1"
weight - 110 lbs
I have many dark scars on my chest because I irritated the small whiteheads and such.
They usually go away in the summer once I get dark enough, but at this point, i was getting a little desperate; my prom is coming up and I really just wanted them to go away. So I bought a Loreal spray tan bottle last night and used it as directed. (I've never used any spray tan before, I am naturally relatively tan and get very dark in the summer.)
Previously, the area right in the middle of my chest had been itchy. The skin would feel tight and a little painful. It happened a few times. But it would eventually feel fine. I thought it might be because of the friction between my breasts...maybe?
This morning when I woke up, the middle of my chest, exactly where it would frequently feel irritated, was very pale, and still is. I don't know what happened but it is worrying me. It's not pale just because I may have missed the spot, which I don't think I did, but it looks paler than I ever remember my skin being. I'm really nervous and jumping to conclusions which may or may not be drastic. I've heard of Vitiligo...or maybe this could be some sort of skin cancer. But it developed so suddenly (or, maybe the itching before was a sign) that I don't know what it could be.
Please help me.