I've just had a row with my 14 year old (15 in Feb) as she was about to go to school wearing 'contour' make up along her jawline. It looked grubby and was really badly applied - but that aside I'd asked her not to wear make up in school as it leaves an orangey ring on her uniform collar - and also because I think it's not necessary. So while it looked terrible, the row was more about honesty in that she said she wouldn't wear it and then just went right ahead and did. School rules are that light makeup is ok and she doesn't usually wear much other than some lip gloss and mascara.
She texted me from the train to school to say sorry about arguing but she just wants to look pretty and hates her jawline and chin (jawline and chin are perfectly 'normal'). In the past couple of months she has become more fixated on how she looks and keeps finding fault with her face and body. She also skips breakfast unless we sit and eat with her and even then it feels like she's trying to find ways to hide how little she's eating.
She seems ok in general: works hard and gets good grades, does lots of sport, very little friendship drama, and generally we've a good relationship. This unhappiness with how she looks is a new thing - as is the arguing. She has two older brothers with whom I didn't have this issue - or any issues really other than trying to get them to study a bit more than they wanted to - so this is new territory for me and I want to help her through it as best I can.