Start reknitting what was already knitted. Hopefully correctly this time.
Edited to add: Finally got back to where I was before the knitting gods nailed me, completed that patterned row and it came out perfectly ... no shortage nor excess of stitches. One more patterned row, two more plain rows, and then the bind off! Which means I'm entitled to cast on something new! (because if my quantity of projects in progress drops too low then the knitting gods see that as lack of worship and they'll mess me up in lace instead of plain knitting)