After i had my first child i have stretch marks on my butt and stomach. tried many products, derma roller works the best so far.
ps, don't buy the needle length shorter than 0.5mm, only penetrate the epidermis, which don't work. ebay sells the better ones. I bought 2.0mm from this ebay seller (twodownson)
his price is the lowest, trust me i compared it all... and good quality i would say.
Good luck to you ladies, hope i helped. Share you succesful stories with me~