I'm 22. 5'6''. Around 114-118 pounds at any given day. I've been finding lately I got shallow stretch marks on my inner thighs no matter what I do. No clue why. I'm on the lower side of the BMI scale and my weight doesn't fluctuate much. Maybe some people just have delicate skin? Or our diets are outta wack? Or maybe stretch marks just never heal back up from growth spurts when some people were younger?