How do I get rid of stretch marks?

Okay, I have stretch marks on the inside of my thighs. Im not sure how i got them but they are really bad. Im not fat at all but my thighs are kind of big. The marks are whitish and kind of silvery. Im 13. Is there a medicine that works really well on stretch marks that already turned white? I heard that they are harder to get rid of when they are white. Do you think that i should get lazer surgery on them at this young of age if the medicine doesnt work? Please hep! Thank you