I dyed my hair brown last night, and it turned out with a tint of green. How do I get the green tint out?

When dying your hair you need to look at the color wheel. The color that neutralizes green is red. Sooo, you can redye your hair with a color like auburn or something with golden or red tones in it. It won't hurt your hair to dye it a second time, you're adding color pigment, so your hair will be fine if you dye it twice. Good luck!