hm... not really sure what you can do because stretch marks is a scar tissue (are different than undamaged skin cells)
you can try 'bio oil' -- it's a little orangey-bottle.
I've used it on scars (stretch, surgery etc) but I keep forgetting so I don't use it too regularly; therefore, have no results to tell you, lol
my cousins have used it too, so no harm in trying. just but a little on every day -- just be careful 'cause it will seep into your clothes
it takes a LONG time to work though -- as would anything else
"Even a broken clock is right twice a day."