Minutus

Any thoughts on this:
We've had a cockatiel for 7 years, his first 6 years he was apparently
abused and it is not certain whether a nodule on his wing was from the
abuse or a birth defect. He is a pleasant bird and enjoys being around
us but if our hands get to close to him, he will hiss and bite at the
hands however we can stick our face right up to him and he doesn't mind
at all. He can't fly due to the issue of his wing and will often leave
his cage on his own via a ladder to come to where we are in the house
to be with us. "He" recently laid several eggs. Obviously we've been
wrong about her gender all these years. She seemed to have went through
the egg laying process normally, she found a place to nest, sitting on
her eggs for 30 days, then returning back to her cage. Now however,
this growth on her wing has taken on a life of its own. Its grown to
the size of marble at least (before it was smaller than a pea) and she
picks at it with her beak, then squack with pain and it bleeds. Its
turned black and crusty.
She's never been treated for the abuse, so would I start there or just
focus on the growth of the nodule and its rapid growth after her laying
eggs for the first time? (seems to be related)
Thanks
~JT