Rest your voice. One day of missed work will not kill your back account.
The only remedy I know for laryngitis involves alcohol and I assume your underage. If your folks approve, i'd be happy to let you know. It also involves fish oil, so don't get excited about it.
As a more drastic measure you can get a cortisone shot, but they are not the best for you. As a LAST RESORT, If you must sing you can chew on a aspirin right before you sing (just cheap generic stuff. You don't want to deal with the sugar coating). That will instantly take down the swelling of your vocal chords, but it is not good for your voice long term. It's just plain not good for you, period. Only for an emergency.
"If this is going to be a Christian nation that doesn't help the poor, either we have to pretend that Jesus was just as selfish as we are, or we've got to acknowledge that He commanded us to love the poor and serve the needy without condition and then admit that we just don't want to do it." -Stephen Colbert