What is the correct supplement for this?

There are these calcium magnesium with zinc vitamins, you are supposed to take 3 a day, I am mainly worried worried about the zinc, it has 167% of your daily supposed to have supplement or whatever. What is the correct dosage for an 11 year old girl? I'm actually 14, but my sister is 11, she has kinda bad skin and heard zinc can help it, and I want to help her.