My 3 y/o Discus has hole in the head, please help her!

Today I found out my favorite fish "Jackie" ( I would like to think
she is a girl) has hole in the head.
She has not lost her appetite & is behaving normally except for
sometimes trying to scratch herself on the driftwood.
I read somewhere on the net that earthworms fed to the fish by itself
will cure it without a need to use medication, I will also perform
50% water change twice a week until she cures herself & then go back to
my maintenance schedule of a 50% water change every other week.
I would like to stick to the earthworm method because I never liked
the Idea of using medication on my tank, and my former quarantine tanks
1 is full of guppy fry and the other, a 30 gallon tank is empty & has
no filter, so If i were to use medication it would have to be in the
main tank.
My x girlfriend added the rams, the gouramis & a female guppy without
placing them in quarantine before introducing them to the tank. But
maybe that is not part of the problem, or perhaps I am wrong.
If anyone has an advice Jackie & I will be very grateful. And if anyone
thinks different I encourage them to post their advice anything that
can be useful.

Thanks in advance.

55 gallon Tank
Emperor 400 Power Filter
ph 6.8-7.0
Temp 82-84
ammonia nitrites & nitrates 0
5 Aponogeton plants from Wal-Mart

1 6" Discus
2 4" Clown Loaches
8 Cardinal Tetras
5 Fancy Guppies
5 Ottos
5 Amano Shrimp
2 Dwarf Gouramis
3 Zebra Danios
2 German Blue Rams