Firstly is it supposed to burn your eyes like this 
Secondly - I have a pixie cut so I've used half of each bottle (the developer/dye that you mix).
They say not to keep any of it - is this because they want you to by more, or will it oxidise and burn my head off?
Its a L'oreal preference thing. Gor it stings a bit. Didn't do a patch test as I've had dozens of salon bleach/highlight jobs and various henna/darker.permanent.colours at home, but beginning to wonder if I should have done...