Burning

I sink down in my seat so far that my chin is nearly level with the desk and stare at the off-white tiles flecked with color, the kind that are supposed to hide how dirty they are. I know that everyone looking at me. My face is on fire, I can feel it turning red as I try to disappear by sheer willpower. They call this blushing. I call it burning.

This is pretty good, but it's a bit of a run-on. Try breaking these sentences down a bit with commas or by switching them up and you'll have a better flow. Other than that, I think this is pretty solid. I like the way you concluded it, there was almost an edge to the words, and it had a lot of personality.
Keep writing,
StoryWeaver

It was so short! I liked it a lot, but I wish you had gone into more detail of why the character was blushing/burning. It would have been interesting to find out. The description was really good though; I know exactly what you're talking about.
I think you should break down the sentences a little bit more. It was kind of hard for me to read because they kept going and going.
Overall, I really liked it.