I usually use fiberglass resin to repair the edges of my boards.
Sand it down a bit, clean up the loose bits. Set the board upside down, put some painters tape on the rounded edge of the board with about 1/2" over laying the edge. Fill the gap with resin/hardener. Allow to dry, peel the tape and shape with some sand paper, file, or a dremel tool. It'll be good as new in no-time.