Here is a beautiful hemmed picot edge technique that will make your top-down socks look so cute.
How To Make a Picot Hem: CO using long-tail cast-on. Work in Stockinette st for 5 rows. Next row: YO, K2tog across. Work in Stockinette st for 5 rows. Next row: fold knitting at lace row and knit each stitch on the needle together with the purl bump from the cast-on row in the column directly below the stitch.