Don't know about High School, and I'm sure it varies from place to place. But in college football, if you are ejected in the first half, you sit the rest of the game. If you are ejected in the second half, you sit the rest of that game and the first half of the next game.
I've never heard of a one-series ejection either. Every one I've seen, they are required to leave the field as well.
I don't really follow HS football that much.
Aries
~Sign of the Rams