My bf slapped my face so hard :(?

ok so we were in the middle of a ^mild^ argument, he was in the kitchen n while he was lookin inside the fridge's freezer i started walkin to the kitchen (he didnt notice- he thought im still in the living room) ... so he wide-opens his hands to like make his point, and his right hand slapped me so hard... i started crying n then he quickly came to hold me and sayin 'im sorry im sorry'.. i didnt listen and just cried harder,,, so he burst into tears , crying harder than me... I pushed him bak and just left his house... I feel so bad , the whole thing was a mess.. what should i do? how should i do it... i feel bad cuz it was all accidental