yo man, the stretch marks you have are really nothing to worry about. Trust me you should be happy that they are not clear at-all. Personally i have stretch marks that cover almost all my sides and are in a reddish brown color (and have been like that for years). Adding to that, i got them on my back side, thighs, calves, and near my shoulders (from excessive body building).
My advise to you is, maintain your weight, dont try to gain or lose much weight too quickly, and you know what, just live with them, because there really isnt a permanent remedy for all this....(not trying to depress you, i really feel your pain)
So, dont sweat about it, you should be glad thatthey are not that noticable, and glad that you do not have another type of skin problem