How to treat?

Hey, it's me (again).

So yesterday afternoon in gym class I fell on the floor and kind of slid across the floor, if you know what I mean.

My leggings broke, and a piece of them was stuck in my knee because I had scraped it a bit. It didn't bleed, but it hurt incredibly badly and didn't look very appetizing. Anyway, I quickly went to the bathroom and tried to get the piece of fabric out of my knee with a wet cloth, because I think it might have become infected otherwise.

When I got home I put a plaster on it and a bandage around it, it worked well and didn't hurt as much anymore, this morning I took the plaster off and put a new plaster and bandage on it, but then I took the bandage and the plaster off and taking the plaster off hurt so much, I think the plaster was stuck to the skin and that's why it was so hard to come off.

Well, my question is what should I put on it? I'll definitely leave it open and dry tonight, but when I put on jeans I'd like to put something on it because I'm worried it'll get caught otherwise. Does anyone have any tips? Or does anyone know the fastest way to make it heal?

Ps since I took the plaster off earlier the wound hurts a lot again, especially when walking and moving.