Swelling on 1 side of birds face

by Alanna
(Brisbane, Australia)

I have a crested pigeon I found and have been hand raising as no wild life carers would take him and he is probably close to a few months old now. I have been trying to get him to eat a more balanced diet but he is not good at pecking seed & so I still feed him egg & biscuit too.

I have just noticed a swelling on one side of his face that extends from his neck at the base of his beak to around his right eye. There doesnt appear to be a discharge, he is still eating and his droppings havent changed. Could you give me any advice, I'm really worried about him?