The picture has some motion blur “uncooperative models, what can you do!” So it’s a little hard to tell, I can see she has some feather loss from breeding or something else, she could have a skin infection starting, she could have mites that are causing an inflamitory response or a secondary bacterial infection.
Some respiratory illnesses can cause facial swelling, sometimes other symptoms can be subtle, look for snicking, head flicking, huffing, runny nose, scratching.
You could some of those symptoms if it’s a skin infection alone too.
You can crush a clove of garlic in a bucket of water for her, garlic can help clear up some skin issues and deter mites, though there are some more serious causes of skin infections like staph or cellulitis which garlic won’t treat so keep a close watch on her, if she worsens consider getting her looked at by a vet or put her on antibiotics.