Patch of Discolored Skin in the Chest Area

Hi, I had the same thing last summer when I went to vacation. Right on my chest, under the left shoulder there was a patch of discolored skin. It was small but visible, and anyone could notice it. I thought it was just a scar left from a big pimple or something like that. Few weeks later, I got another patch of discolored skin also on my chest, but under my right shoulder. I started panicking, because I thought I had herpes, fungus or something like that. I was scared that my whole body will be covered in discolored patches soon. I went to dermatologist, and she asked me lot of questions. It turned out that perfume caused those white areas on the skin. I was exposing my self to the sun every single day, because I spent most of my time on beaches. The perfume contained alcohol and some other supplements that shouldn’t be exposed to the sun.

JUST NOTICED IT TODAY,NO IDEA WHAT IT IS . THE SKIN IS DISCOLORED BETWEEN SHOULDERS AND AT THE TOP OF THE BREST
BONE AND CONTINUES DOWN THE BUT STOPS AT DIAPHRAGH AREA.
KIND OF A BROWNISH-RED . ANY IDEAS ?

I noticed a redish brown discolored area on my rib bone under left breast area. Does not itch, is not raised - just darker. then weeks later a round one larger than a silver dollar on my lower stomach also left side, then up pop 3 then 5 small dime to quarter sized on my right side stomach. None itch or are bothersome - just brownish redish color. I have a Dr apt in 2 weeks as Ive had this now going on 3 months.

My son has an 8 inch discolored spot on the upper chest. He has had it for several years. Doctor recently said to have it checked. What could it be?