Re: I'll never try that again.
RR, what you need is effects. Lots of lots of overdubs and effects :) Echo like the Grand Canyon. Delay to take you to next week. Dub FX over the top of bad moments. Change the pitch of your bum notes. Cheat, lie, beg, borrow and steal - that's what the pros do. The aim is to produce something enjoyable to listen to, not to prove that you can pull it off without cheating.
If it really is irretrievable then you could try playing it backwards and going crazy with hi and lo pass filters, noise filters and truncations ... create a psychedelic masterpiece!
Or ... you can practice and record the song for a few weeks until your performance improves :)