I just had an intense practice last night. I had to sing strong and high for most of the song. I feel my throat is a little sore. I need to do this again tomorrow night and the actual performance is on Easter Sunday. What can I do to recover quickly?
You can try to see a laryngologist for advice. Maybe there is something that can reduce the swelling, but I would recommend you use it only if you have a good coach who can help you not further damage your voice with the medication.
The most responsible part of me needs to answer that there may be nothing you can do at this point. You might have to cancel your performance, or sing it less loudly, or ask them to lower the key.
It will be best if you do not rehearse again – just rest and maybe your voice will hold up for the performance.
Most importantly, you have to learn how to sing in the first place so that this kind of fatigue does not happen. Singing high notes with volume is a matter of refining technique so that you have amazing resonance. VOLUME AND PITCH SHOULD NEVER BE ACHIEVED BY FORCING OR TIRING THE VOICE.