Birth Control

My parents are pretty against me going on birth control for any reason. I have horrible periods, awful acne, and I am sexually active. I'd honestly like to be on bc more for my acne than anything. I've tried to suggest getting on it for my periods even before I was in a relationship, and they didn't want me to. I know I can go get it myself, but I'd like my mom to be by my side. How do I mention it without suggesting I want it for sex?