So painful when this happens! Take a look at the last row that you did and go back over the pattern instructions, namiing each stitch on the needle as you go. You may be able to identify the extra that way. Another possibliity is to insert a needle a couple of rows back then rip out to that point (keeping count of the rows you rip out) and again name the sts on the row that's on the new needle. Here's a video for inserting a needle
in a destination row. It's more difficult with a lace pattern but perhaps you can do it on a wrong side purl row?
This won't help now but it will once you get back on track. Use a lifeline
. It'll save wrry about ripping out and picking up sts if this should ever happen again.