Suggest Treatment For Pink And Fluffy Cheek Of A Child Post Injury
Shouldn't be an infection.
Detailed Answer:
I read your question carefully and I understand your concern.
Judging from that description though I do not think there is an infection at play, at least not an infection from the wound. Local temperature and pain are two of the main signs of an infection and fortunately you have checked those to be absent. An infection from the wound would have the wound as its center and the wound looks fine from the photo.
As to what it actually is it can't be said with certainty perhaps it's a tooth coming out or some other teeth issue. The so called slapped cheek disease would be another hypothesis but that usually involves both cheeks and has some low grade fever. But I as long as there is no fever, newly appearing pain or other symptoms I wouldn't be alarmed.
I hope to have been of help
You're welcome.
Detailed Answer:
Wishing you good health.