The whole incident was a complete freak accident, Hischier tried to cut in front of the net with the puck, but ending up falling down and got tangled up with two Czech defenceman on the play. One defenceman's skate brushed just against his face, but thankfully didn't make contact.
Hischier was bleeding quite a bit from his face, to the point where he had to go to the locker room to get stitched up and replace his jersey, which was covered in blood. Hischier wore his usual number 13, but after the incident he came back out with a number 49.
The game went to the shootout, and Hischier wasn't selected for team Switzerland, which goes to show that he was not 100% okay even at that point of the game.
Reasons like this is why international hockey involving NHLers has been so scare. Hischier just narrowly escaped an unthinkable situation, and frankly, the NHL hates when that occurs not on their watch.