Without a picture its hard to say, but usually with popeye or similar maladies there isn't much you can do except let it heal on its own. Usually problems with the fish's skin stem from less than adequate water quality. You don't say anything about your maintenance practices, but don't be afraid to keep up with your regular weekly water changes just because there are fry in the tank. In fact, with the extra fish load you will need to change water more often for good fish health.