Thank you so much for your great suggestions on how to solve my Citron problem. I tried Rudee's suggestion of blocking, then I tried to frog back, per Sydney's suggestion; neither one worked. I think the problem began when I had to cut the yarn. Actually, I think the problem started when I accidentally used the yarn coming from inside the ball instead of outside, like I usually do. Eventually the yarn kept tangling worse and worse and so I decided to cut it, and continue knitting with the outside tail of yarn and I think, somehow, that caused the offensive ridge. (Although it could have been a rogue short row.)
I was complaining and whining to Steve about how aggravating it was going to be to have to start over (I had almost completed the second section), when he asked me an important question.
Me: whine, whine, whine, etc.
Steve: But I thought you liked this pattern?
Me: Yes, but now I have to start over.
Steve: But if you like it, won't starting over mean you just get to knit it again? And since you like it, what's the problem?
So I realized that he was right. I really was enjoying the pattern, and starting over means I get to enjoy it for a little extra time. Not that I want to knit it forever or anything. Sisyphus, I'm not.
Now my concern is that I've messed up enough of this skein of yarn that I'm going to run short at the end, but I love the color so much that I'm going to give it a shot. It may be the shortest Citron in the Ravelry pool, but que sera sera.