A metal object does not distort and absorb the deceleration of the head. A hand will flex and distort reducing the deceleration. Acceleration or deceleration is change of speed over time. A metal object makes the impact time very short so the deceleration value is high. An impact of a hand has a longer duration of impact plus the head moves in reaction to the impact force spreading the impact duration. The mass of the hand is also less.

A head is 8 to 11 pounds into a fixed metal object. A hand is 1 to 2 pounds that flex and distort as it hits.

But, a hit to the upper neck can cause trauma to the upper neck with much less force than needed for a concussion. 5 Gs can cause whiplash. 60 to 85 Gs are needed for a concussion.

What does it matter if you received a concussion or an upper neck injury, sometimes called a cervical or brain stem concussion. You deal with the symptoms, not the mechanism of injury.

Yes, the smack messed you up. You will recover but still be at risk of your father doing it again.