Wow. This poem hits hard. It doesn't hold anything back, and it's an issue that children/teens/young adults deal with on a daily basis. The subject matter is raw and I like it.

The title drew me in and the words kept me reading. You have taken the laughter of other people and turned it on them. A great skill to possess. The inclusion of quotes gives this poem a pulse.

As a writer myself, I find it hard to critique subject matter that seems personal. I feel like I am critiquing someone else's emotions and experience. But then again, isn't all poetry emotion and experience? And with that, I have a few tips or suggestions. I hope they help in your writing journey.

1) Line breaks add weight

“You’re fat. You’re dumb. You’re a waste of space.” Words are powerful. I believe they have the power to speak life or death. And this poem shows that. You should give each statement it's own line if you want the weight of the words to sink into the reader. Maybe “You’re fat. / You’re dumb. / You’re a waste of space.” OR “You’re fat. You’re dumb. / You’re a waste of space.” I do believe that the waste of space comment needs to stand on its own. Those words are harsh and need to be felt by themselves.

2) Symmetry in your repletion

"Is it funny that your words have made my grades plummet?" In the previous line you did not include the word "have". I think you should also leave it out of this line because it follows the same pattern. Entirely up to you.

3) "that the blades"

This line would sound better with the 'the' removed. Listen to it both ways and see which one you prefer.

4) "My sides hurt from laughter." Or you could say "my wrists" since you referenced blades earlier.

I know I left a lot of comments here and suggestions. But I did enjoy the poem. Don't take my suggestions blindly. You have your own style and should follow your own writing rules. These are just spots that tripped me up as a reader.

Keep writing =)