Melt candy. Melt Blueberry Lemonade candy according to package directions.
Prepare decorating bag with melted candy; cut ¼ in. from tip of bag. Pipe melted candy on top of cake, then pipe drips down side of cake. Immediately top cake with some of the remaining sprinkles. Chill cake until set, about 10 to 15 minutes. Reserve remaining melted candy and sprinkles for later step.