Michelle, I realize you probably finished the dress by now, I think the did add a fabric placket under the lace trim. If you look at the drawing of the pattern pieces you fill see one long slightly curved piece, number 4. I have cut that out of the fabric, 4 times for the plackets, to make them double so that all edges will be finished nicely. I'm not adding lace though. I think those raw edges could be finished even with a bias tape after applying the lace maybe?...

Alisek, Very pretty dress!