I am sick of it!?

I am 14 and i have an anoying bit of weight on my stomach and thighs. My arms, face, chin, calves and bum are slim.
How can i lose weight from these areas safely? What exercises are good for these areas? Also on the tops of my thighs are these weird small purple lines, but there not stretch marks, how do i get rid of them?

Leg crunches (or squats), & sit-ups. The purple lines could be blood vessels that were suspended in a fat layer, & are now exposed between the muscle & skin — as the skin shrinks, it should thicken a bit. This should make the lines less visible.

MegaFitness.com Crunch Belly Butt and Thighs Bootcamp Teri A