I haven't made this pattern but have just read the instructions for the ruffles, and yes it seems that the ruffles are raw edge. Cutting the fabric on the bias will help prevent fraying. I would make and put the ruffles on the dress as the instructions say, no hem on the ruffles at all. If you are really worried about the edges fraying you could overlock the edges with some matching thread. You can PM me if you want to discuss further