Cholesterol help?

Hi I’m a 14 year old girl and Im 120 lbs and 5’9. I’m taking this pill to get rid of my acne. It’s called Accutane (Isotretinoin) and one of the side effects is raised cholesterol. My dermatologist told me that my cholesterol is 178 and she said it needs to be 170 or lower. So how can I lower my cholesterol and also what does all this mean? Thanks! 🙂