yes or no?

i always find myself letting this certain girl use my hairbrush every single day at school.

so today in lesson she asked if she could borrow my brush because she got green stuff into her hair and wanted to brush it out. I said no because I don’t want unknown green stuff in my brush.

When I was doing my work ( I sit by her boyfriend ) he went into my bag to get the brush for her, she then proceeded to pop the back of the brush off (tangle teaser) to write a note to thank me fo letting her use the brush. I know she did this on purpose and that she got him to go into my bag.

I’m annoyed at her and the boyfriend should I be?