I have a friend who is always trying to out do me in clothes and everything else appearance wise.?

She never use to be like this. And it all started with one of my friends liking her. After that her confidence grew big time ... which is cool ..then she started to act really bigheaded ... like always saying that boys whistle at her and look at her all the time. She tells me this and i really dont care ..i just want to p my Maths A Level .. and this girl is constantly pouting and dressing up so boys look at her when we walk past. Its like she is trying to prove a point to me that she is better looking than me or something because in the past i have always overshadowed her and i guess thats why she is being like this. Trying to prove to herself that she is better than me. Problem is i really dont give a flying monkeys who is better looking. What shall i do?