If he can reach his bandage & toes then the collar is not thick enough. He should not be able to lift his foot high enough to get it to his beak with the proper thickness. Go back & look at the last photo on the bottom right of my B&G macaw I posted. The collar needs to be out past the bottom of the lower mandible. You could try strips of t-shirt to add thickness. Keep in mind once t-shirt material is cut it will roll up some, so cut it wider.
I found another photo with a frontal view.
I found another photo with a frontal view.