Stretch Marks 😫

I'm 16 years old, and I'm 145lbs. I'm fine with that, but starting to work out more. I've had stretch marks since middle school. And recently, I've noticed they are getting worse. They are ALL OVER the inside of both thighs, even down to my butt and close to my 😺. They are also spreading to my calves. And they are more red than normal. I've gained some weight. But nothing drastic. And they're everywhere! I've always been uncomfortable with the size of my legs, and love handles, and now I have stretch marks to worry about too. My boyfriend doesn't mind them. He doesn't even pay attention to them. But I can't stop thinking about them, and I know they won't go away. But I'm getting so self conscious about my body. What are exercises that I can do to get rid of love handles and make my legs slimmer? I hate this 😒