Strange indentations on my back! I would greatly appreciate an explanation!?

About a week ago strange horizontal indentations appeared on my back! one morning i woke up with these, No pain they haven,t got worse, They haven,t got better either. I found a similar question asked by Green bean dance... I believed he refered to them as vertical along his spine and being purplish. In my case it would be lower back. A few the biggest are located well above the line of my elastics but it seems that a few smaller less indented ones lie just below my elastics line. As far as i can tell this happened over night and contrary to green beans description they are more reddish and ranging in length but not generally being longer than about an inch and a half! but yes they certainly do look like scars and they have shown no sign of getting better! its been about a week. I am 15! Any help/advise would be greatly appreciated! I have shown these to my parents I'm one of 6 children they seem to have no better idea! and when my mom described these indentations to our chiropractor he simply said insufficient information! I would rather avoid a doctor trip. And they are causing no pain, They don't worry me any Please someone just give me an idea of what they are and tell me whether they are going to go away any time soon. :\