Mistakes happen, even to the best of us. If you want to undo or redo any of your stitches, try to keep the original magic loop together. It's one of the trickiest techniques in crochet, so you'll thank yourself later for keeping it around.
If your stitch marker is correctly in the first stitch of Round 2 – great! Watch this video to learn how to undo stitches safely and get back to the first stitch of Round 2:
If you forgot to put your stitch marker in, your best bet is to reset back to the magic loop:
If you got a little too gung-ho about undoing stitches and undid some of the magic loop, you'll need to add some stitches back:
Lastly, if you #CantStopWontStop and undid the whole thing, start over by crocheting your own magic loop.
Too hard? Try this way to start a round piece by crocheting a chain instead.