You can get rid of stretch marks using moisturizers on your skin. You can also apply glycolic acid and Retin-A on your skin. Vitamin E oil might also be helpful thou you can get a dermatologist to assist you on this.
I have never have any stretch mark in my life until I got pregnant with my son. I started getting stretch mark on my stomache to my under arm and between my thighs and behind my knees. It was bad. I used co co butter when I started getting these stretch marl but it didn't work on me. I guess it works differently on different skin type. I tried mederma but it didn't work so I just stop trying. But you can try bio oil. I heard its good.