Hi, I am 18, a female, 5 foot 6 inches, 220 pounds and 5 months postpartum. I noticed during my pregnancy that I got a purple line extending from my tail bone, down my butt crack. Then at the top of it, I had a cyst which popped and drained on it s own. Now, 5 months later, the line is still there and is a deep purple. I don t know if maybe this is a stretch mark or something but I was wondering what it could be?