injuries

I’m 15 so am only refereeing youth football. Almost all injuries receive treatment should players leave the pitch until after the restart? Should this be done in adult football too or is it only necessary from a certain level?

I have a couple of questions: 1. If a caution/sending off is not given, it is not a goalkeeper, it is not the result of two players from the same team colliding and it is not a severe injury; are players always removed from the field of play after injury where treatment is required? (A bit...