Help!

I go on stage tonight and tomorrow with Smoke on the Mountain and my voice is a little shot from allergies. Any home remidies to get my voice ready for tonight besides water (been drinking all day long)? I can talk and sing now but not sure about later...and I may have a nagging cough on stage...uggggh! A first time for everything!

The staight lemon juice is great for right now but will kill your voice tomorrow.  Pineapple juice will give you a boost of about five minutes of voice, but drinking that everytime you run off stage will have you peeing like a racehorse by intermission.  Good luck.

 No expert I'm still waiting for mine to mend, after it broke.
Consult a local or your vioce coach., but in the mean time.
Lay off throat lozeges & quick fix remedies, they only a mask & are a short term mesure at best -  you will pay for it later!  A sore throat is the bodies signal that the vocal chords need to rest & heal.
Drop all the dairy products & alcahol, rely on your diaphram, breathing, warm up  & down exercises.
What I noticed over the years with pro opera & other singers, is they mix up honey in cider vinegar & gargle with it, prior to performance not during it. Let your throat tell you how far you can push, not the pressure of performance. Get a mask to cover your eyes & don't read or watch TV, switch the radio off. This probably sounds stupid, but in fact reading & while listening to music, your vocal chords are working, without you knowing.
Those who have damaged thier vioce have to go thru the same process of healing, so rest them, close your eyes & shut your gob!
With the performance, try speak/singing, only singing the beginning & end of each line & using speak to saliant parts of the story, untill your vioce is capable of handling it again.
During the peformance, while your off stage resting cover your eyes & put a pair of ear muffs on. Even if you look like an idiot, remember your protecting a delicate instrument & don't laugh!l

There is the 'entertainers secret' http://www.entertainers-secret.com.au/?gclid=CJCBtNWk_o0CFRS7YAod0lg6Sw 
But I would say only use it after you have recovered?

Vioce Coat & entertianers secret would be the same horse. just with a different jockey.
Which are great for a quick fix & if you need to sustain long prolonged singing periods.
Inverably a lot of trained singers, espicialy in the pop rock 'n roll industry, use thier false larynx, which enables them to scream/sing for extended periods, much the same as cats do.
With the reading bit, this came up a number of times, when singers have consulted with vioce pathologists after they have experianced vocal damage. It sounds stupid, but apparently true.
The only patholigy I understand is how to effect an instalation, using bricks & cement.

http://altmedicine.about.com/cs/allergiesasthma/a/SinusIrrigation.htm