Here is another home remedy that I used in desperation last year when I had almost lost my voice before a performance. I could barely talk, and called my voice coach/mentor in desperation. She said that the last resort was an old opera singer's trick... gross, but I did it.
Buy a small jar or can of anchovies. Take a piece of anchovey and place it far back on your tongue and hold it there as long as possible, sucking the salt out of it. (yuk) The fish/olive oil and salt does something that helps. Spit out each piece and add a new one as the salt dissolves. Do this as long as you can. I couldn't talk, but amazingly I could sing. The other important component was using good technique, lots of breath support so I could flood each note with air. No one could tell I had laryngitis, unless I tried to talk. I did have second thoughts later when I realized that I could have really messed up my vocal cords by singing when my vocal cords were in bad shape.