Can you link to your pattern? or what's it's name and where did you get it?
It sounds like you should have been told to put stitches on a holder or leave them unworked on the needle. Do you still have live stitches? Unless you've already worked the other shoulder, and it doesn't look that way from your post, the stitches must be somewhere.
Happiness is catching that dropped stitch while it's still fixable..