See if you can recognize some stitch pattern and rip back to one row before that stitch (maybe a recognizable yarn over?), then un-knit one stitch at a time to leave the row that you recognize on the needle.
In order to save yourself this problem in the future, it's a good idea to insert a lifeline. That way, you can rip back to the lifeline, reinsert the needle and know where you are. There's a video on the Tips section of Free Videos called Fixing Mistakes that wil show you how to do the lifeline. Use one every so often and it will help enormously.