In stockinette stitch: To rescue a dropped stitch from the knit side of stockinette stitch (if the purl side is facing, turn it around), reach through the dropped stitch with a crochet hook and pick up the bottommost strand in the ladder. Then, pull the strand through the stitch toward you to form a new stitch.
A dropped stitch is one that has come off the needle. Whether it is a dropped knit stitch or purl stitch, fear not. You can fix it. You might see it right away after you .
Knit until you've reached the dropped stitch. Insert a crochet hook (if you don't have one available, the top of your needle will also work) into the loop of the dropped stitch. Now grab the bar of the stitch right above it in the crook of your crochet hook. Pull the bar through the stitch.
A running stitch is one that has dropped more than one row. It is easiest to pick it up with a crochet hook. For a knit stitch, be sure the loose horizontal strands are .