Are you sure about that? I thought it was you automatically missed your next competitive game, no matter what competition... I can't find the FAI J C rules on the web. But the Munster Junior cup states:
Any player sent off in a match in these competitions automatically incurs a suspension from the next competitive club match. A player sent from the field of play shall serve an automatic suspension at the same level of club football. (i.e. a player sent from the field of play in a 1st team fixture may not serve an automatic suspension in a reserve team fixture and vice-verse) Following receipt of the referees report the disciplinary committee may at its discretion extend the duration of the suspension and / or impose fines.
NOTE: There is no appeal against an automatic suspension except in the case of mistaken identity.