Depends on if he just lied or not. If he lied and said that, the truth would cancel out the lie and it would not grow. If he told the truth and said that it would grow, it would be a lie, thus canceling out the truth and the world as we know it could come to an abrupt halt. That's if you'd listen to the word of a wooden marionette to begin with.
His head would explode due to a paradox because if it didn't grow then he'd be a liar and it'd grow but then that would result in him telling the truth and it wouldn't grow. So if he said that there would be no more Pinocchio.