You've probably already seen this...but Amy's "lifeline" video I think would be great in this situation. That way you only have to rip out a few rows instead of start over.
Here is a quote from one of Amy's posts:
Inserting a lifeline [Edited...I've improved this idea!] There's a big shortcut you can use with interchangeable needles, if you're doing lacework and want to insert a lifeline (what's a lifeline? Video on this page). Instead of threading a tapestry needle with cord and running it through the stitches, you thread the Knitting Needle itself, and let it work the cord in as you knit! There's a little hole in the Boye set (you know, that hole that the tightening tool goes into) that could have been designed for this purpose!! I haven't tried it, but I'm thinking you could slip the cord into the hole of the denise needle before locking it onto the cable. ...Hope that makes sense, what I'm talking about.