Friend doesn't want to go to homecoming because she feels ugly?

She has never been to a school dance before because her parents are very strict, but recently they decided to let her go since she's in high school now. All of our friends are going (my school has a really late homecoming, idk why) and no one really has a date, but she doesn't feel confident enough about herself to go. I know I can't force her to go if she doesn't want to go, but I don't know what to do. Her main reason she feels not confident is because of her acne and even though I told her everyone goes through it she insists it's only her. Even besides the fact of homecoming, I want to help her feel more confident about herself. Any suggestions?