Okay, i just screwed my hair up big time.?

I died it, & the lady obviously didn't know what she was doing. my hair is naturally plat. blonde. & now the only blonde you can see is my roots, it's like 9:30 and i can't really go back now. Plus, it's winter so I can't really go sit out in the sun with sun in, or lemon juice. & i really need to fix it before school tomorrow. help?!