It would be tough. You'd have to take out the top of the hat, unravel down to that stitch, assuming that there are no decreases between the top and the twisted stitch--it would be hard to get the dec back correctly. Then you'd have to unravel the one line of stitches down to the twisted one and bring them back up with a crochet hook. If you had discovered it before you finished, I'd say go for it; but at this point, I'd consider it a 'design feature.
' and let it go.