wow, you did a really nice thing trying to save those rays. Good luck with it and I hope they all pull through.
A few months back one of my rays had a cut on his forehead(never found out if it was from the heater or from him trying to jump out of the tank and slamming into the cover)-the cut was not nearly as severe as these rays are but I added extra prime to the water and in a few days it started scabbing over, then the scab fell off and now it just looks like a lighter patch of skin between his eyes. Have you been adding and prime to the water? salt? Good luck with them