Most of the fixes suggested are too long-term for you, and some are of dubious merit anyway.
To feel better tomorrow, drink lots of water or gatorade or any liquid...aim for 2 liters a day. Eat normal food, but maybe not really fatty stuff. Pasta with meat sauce is delicious and good. Take Advil (generic: ibuprofen) or Aleve (generic: naproxen). I usually take 2X the recommended dosage of ibuprofen (usually 4 capsules), but I am a pretty large guy. Make sure you take the ibuprofen or naproxen with food, else it can irritate your stomach. This is not medical advice, and should not be interpreted as such. But the drugs are pretty safe and available almost anywhere over-the-counter, if you don't already have them in your cabinet.
Ibuprofen and naproxen help reduce inflammation, in addition to reducing pain. The inflammation caused by your overexertion is most likely the cause of your discomfort. Stretching (mildly) may also help, and so might a light workout.
Eating protein "pills" is dumb. Food is tastier and cheaper, among other reasons.
When the audition nears, you can try Icy-Hot, Bengay or similar...but be aware that it will probably numb sensation in the areas you apply it. And don't apply it yourself...using your own hands to apply it will also spread the effect on your hands!
Good luck on the audition!