What should the referee do if the ball hits them and then goes into the goal?

If the ball strikes the referee and then enters the goal, the correct response is to disallow the goal and restart the game with a drop ball. According to the Laws of the Game, a goal cannot be scored directly from a ball that has touched a referee or any other match official while they are still in play. The play is considered affected, and since the referee is an integral part of the field, any contact with them necessitates a stoppage.

Awarding a drop ball is the most appropriate course of action in this scenario, as it allows the game to continue in a fair manner, considering the instance of interference that occurred when the referee was struck by the ball. This ensures that the rules are upheld and that both teams are treated equitably.

The other responses do not align with the established rules: allowing the goal to stand would contradict the regulations, restarting with a corner kick does not relate to this specific situation, and changing possession to the opposing team would not appropriately address the interference by the referee.