04 Mistakes Nobody's perfect and in a pressure situation mistakes do get made.
"The old trick is to say 'no one'll notice that in the mix.' Well if you can't hear it in the mix, what's it doing there in the first place?"
Paul Burns
Studio 64
Middlesbrough
If you know you've made a mistake or you feel that you can do better don't be shy about it.
It could be only a couple of lyrics out of a whole verse that you messed up and if that's the case it's not going to be a problem.
"Punching in" is a common technique where instead of voicing the whole thing again, the engineer just records you doing the bits you need and edits them so they sit seamlessly into the finished verse.
It's better to do 20 takes of a troublesome lyric than just ignore the mistake and hope that other instruments will mask it or that no one will hear it.