How do I stop my self harm and who do I tell?

I always though of self harm and thought that people who did it were stupid , then today people were really nasty towards me and I felt like complete garbage. I cut all over my arm , on my hips , and on my thighs and really burns right now. I don know is who to tell or what to do because I'm feeling like I should do it again.
How do I stop my self harm and who do I tell?
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