If your stretch marks are fresh, they will be colored. ie. red/purple
They might be existing marks that are stretching some more.
I've had stretch marks since high school. I got 'em at the shoulders, waist, inner thigh and more places I'm sure
I have read in many places that stretch marks are directly affected by hormones. They usually arise early on in youth (high hormonal activity during youth) or when the body changes (pregnancy, bodybuilding, growth, etc.) When the body changes this way, hormones can become hectic and this is the result. A lot of people misconceive this with getting big too fast but it is not the case...it is hormones, hormones play a big role in the development of the body and this is why people confuse the actual reasons.
No cream will work. Laser surgery has shown only improvements but nothing has been found to make them go away completely. Over time they will fade. Don't let them get to you...they are part of who you are...don't be shy about them...just learn to live with them. I'm sure there is some kind of surgery you can have to actually remove this skin or whatnot...but it is sure as hell not worth it.
I'm no stretch mark expert, but have read a lot on this subject since I am afflicted with these...the best thing I can say is see your doctor and ask him what you can do to prevent these...that's what I did and he told me there isn't much you can do...but give it a shot...you never know if one of them has finaly found out an answer.
Keep working out man, don't let puny stretch marks get in your way!
