1. With make-ups, the bible tells us that we should not glory or rejoice in our out-ward appearence, but in that which is the heart (meaning righteousness). External make-ups tend to present the one who wears them as one who is after the praises of fellow human beings - but the person who is after the praises of God will be more concern about internal make-up (which is heart purity and humbleness)
2. As for trousers, the bible further tells us that we should not live out lives in a way that we makes the people around us to fall into sin. When women put on trousers or mini-skirts (or any other sexual oriented clothing) they creating a platform for men lust over (men are tempted to desire to sleep with them) and that on its own is a sin before God.
Please do comment under this self same question if you have further questions and we will gladly try reason with you.