I dyed my hair about a week and a half ago. It was a kind of auburn red color and I wanted it more red/violet but it came out too dark. So I've been showering with boiling water all the time and not using color safe shampoo because i want it to get lighter. It has, but only a little. I'm trying to get it lighter and redder. If I add lemon juice to it, will it work? I don't want it to turn orange.

How much should I add to the shampoo? Fresh lemons or bottled lemon juice?