<human>: Could you distill the essence of the text into 1-3 sentences?

Okay so, my best friend who has always been there for me and vice versa, had been cutting her thighs really badly and self-harming. Her boyfriend, a therapist, and I helped her through it, and she is over 6 months clean. 

However, her and her boyfriend broke up, and since I was on vacation, she became good friends with this girl that wasn't very stable and was not the greatest influence. She convinces her to do various things with her and gets her into dangerous situations, and because of this she's been doing things that are out of character for her, like hooking up with several guys, drinking, taking off her clothes in front of boys, sneaking out, hooking up with upperclassmen, etc...

I'm just scared that when she gets to high school, reality will hit and people will talk about her behind her back. If she finds out that people are using her/gets hurt in general, she will start self harming again. I just don't know how to tell her to stop and that she's acting VERY impulsively and is hanging out with someone who could potentially hurt her. What do I tell her? I really don't want to sound rude when I say it.
<bot>: My friend is hanging out with bad influences and doing things that are harming her physically and emotionally, and I'm afraid that she might go back to self harming again. What do I say to let her know that she is worrying me?