My sick flowerhorn. How do I cure this?

[6 bar]

Here's a pic of my flowerhorn's head:

It started off looking like 2 white head pimples, then it looked like the zit popped. And now it looks like the meet is all rotten and the wound has spread all over the forehead.

I just did a 50% water change, put in some parasite meds and melafix.
He reluctantly eats now, and has only recently downed some mp.
Any ideas on what it is and how to cure it?

 

[6 bar]

Here's a pick a few days ago before that wound just blew up.
If you look closely there are small openings on the forehead right before the eye.

 

[scottgeeze]

It might be hole in the head disease.