It was a terrible dilemma for me. I hate being asked questions by strangers, and I hate people making false assumptions about me, so I was tempted to call work and say I'd be a little late today and then spend the time trying to dye the white back to my natural color, to avoid being asked questions and having people assume that I had been feeling some deep psychological need to make myself look all punk and cool or something. But I also do not like the feeling of worrying about changing my own appearance because of what other people will think - it takes more courage to just leave it however it is and resolve not to care what they think. And the half-white hair wasn't really that bad, objectively speaking; it was just the questions and assumptions from others that I was dreading and panicking over.
Now I am experiencing great relief that none of this actually happened.