feather cyst

He's been biting at the area for almost a year. Got a scab rips it off then started again. However in the last few days it got like this? He was just at the vet and said the scab was to large to see what's going under there.

Every day i wonder if I'm doing the right thing by pickle. Pickle is my 2year old male red sided Eclectus and he was diagnosed with Chronic beak and feather earlier this year. I know i normalise everything about him, playing with him every day how could i not?.. I just don't want to be the worst...