Frequent large water changes, salt, and cut back on the feeding to no more than once a day. As long as you don't overfeed and keep the nitrates under 20 ppm HITH should not be a problem.
Messy poor quality water is the cause. Like said above, cut down the feeding and make sure that the tank is being cleaned regularly, not overcrowded and has adequate filtration.
Hole in the head is usually poor diet and/or poor water quality. Avoid feeders and keep up on those water changes. Make sure your fish gets a varied healthy diet.