What is causing this dark spot?!

I have a dark spot (looks like a birht mark) in the middle of my neck right above my collarbone that was never there before. I have been on birth control for a few years, and I know that BC pills can sometimes cause dark spots when you tan, but I have tanned multiple times in the past few years and even spent a week under strong sun in Tahiti and never had any spots. I've heard that pregnancy can cause spots like this, but ppl in the pregnancy section seem to think I'm crazy. Anyone have any ideas.? Thank you!Health Question & Answer

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