You and him where arguing and he was starting to lose his temper. After a few minutes he looked at you with a crazy look in his eyes before back backhanding you across the face as hard as he could, leaving a mark

"I SWEAR WILL YOU JUST SHUT UP!?"

You froze , with the stinging pain on your cheek. Not hurt because of the pain, but the fact you got slapped off by the one whom you thought you meant something.