Your profile tells me nothing of you and what you practice and how long you have been practicing.
If you are new, which I will assume, you should not even be doing this. Harming someone with no knowledge about magic or how it works, then it could harm you too.
I suggest you learn magic before you harm others and yourself in the process.
Also, harming someone in general is risky. It takes a very knowledgeable and experienced person do actually harm others and not feel any harm in return.
Don't let anger rule you. Think about this.