@ Elizabeth, it's karma. some people don't believe in it, but whatever you want to call it, you need to be careful what you wished for. magic has no colour, nothing with magic is that black and white. in my opinion it's good to classify in colours when you're starting out, but there isn't any colours, and it's a bad habit to do.
taking this spell for example, let's say you cast it on a girl who you don't like. you're casting it without any reason beyond 'i wanna see you suffer' or 'i wonder if this will work' or something like that. this would result in the spell to backfire, because you're just getting revenge on someone. maybe the spell does work and you don't get the curses effects attacking you, but you might feel other negative effects. say you get food poisoning one day, even though your friends had the same thing, or you loose something close to you, a friend is mad for no reason. it could be little things lover a long time, or it could be one big thing.
you should think before casting any spell. a health spell for a friend, while you are helping, maybe that friend doesn't believe in magic, and they get really mad at you for casting. perhaps they never find out, but for some reason they're grouchy around you. love spells are particularly sticky. you want a guy, so you cast a spell to bring love into your life, no harm. you cast a spell on a person at school to love you, this is when you have issues. you are toying with a persons free will, maybe you two weren't destined to fall in love, maybe he, or in fact yourself, was to bump into someone that day you cast who was your 'true love' but you cast this spell, so you walk home with them and miss the person you were meant to be with. one day, you may look at him and realize, he doesn't love you, it's all the result of this spell. love spells tend to dish out guilt more than broken bones.
anyway, to the post at hand, i've seen this before on other sites, and similar spells here as well. i like how you wrote this in the first person when it's clearly not your spell.
i know of other spells involving similar ingredients but these two are the exact same spell, found on mojo [as listed in an above post] and here on SoM. not that i've tried this spell, but it's rather easy to find if you type 'blackberry leaves' into either sites search engine. you shouldn't post a potentially powerful curse on the forums for anyone to find. granted people looking for it will find it either way, but for newcomers who want to try something, you shouldn't have it posted on the forums.