Worried about friends relationship

My friend has been going out with this guy for about 3-4 months, and honestly none of our group of friends are that keen on him - he's quite possessive and rude and gets jealous if she spends time with other guys. But she really liked him so we tried to to get along so it wouldn't cause her discomfort or make her upset but now when it's come to exams she's not bothered at all (she used to revise and try) but now she literally spends all her time with her boyfriend and doesn't study at all- we had an exam today and she didn't answer two of the twenty mark questions. I've tried to tell her she had to work and I've tried to sit down and get her to revise with me but she just goes off with her boyfriend an refuses to work at all- I'm so worried she's throwing her future away- she's naturally clever and I know she has the potential to do great but I don't know how to get her to see sense !! What should I do ? How do I get the message across?? I'm reall y worried she will fail if she keeps going on like this! (sorry it's so long x)

Put the internet to work for you. via Personal Recipe 2629979