How can I make my legs look better?

I’m not that big of a person and I have a pretty normal height-weight ratio. Yet, I have the worst cellulite of any overweight person I have ever seen at the beach. It really lowers my self-esteem to the point where I cry hysterically every time I see my body in the mirror. It’s literally disgusting. Not only do I have that problem, but I have noticeable stretch marks on my thighs, (front, back and inside) and bulging bright red ones on my calves. I also have a bunch of spider veins that are hereditary and unsightly The sad part is, I’m only 17. So now to the actual question, what are some exercises I can do to tighten up my legs/get rid of cellulite? And are there any routines for legs that make them look healthier? (i.e Scrubs)