What did you do to your hair?

For Halloween we spraied Heidi's hair black. She walked into school the morning of her Halloween party and this is what happened:

Jakin (Heidi's friend, also 4 years old): Heidi! You got your hair cut!

Heidi: No, I didn't.

Jakin (looking very confused): Huh?

I left Heidi's class with Jakin still stairing at Heidi wondering if she didn't get her hair cut then what was different about her...