Hello and Welcome to ‘Ask A Doctor’ service.
I have reviewed your query and here is my advice.
From your explanation the red fleshy thing can be
hematoma that can be due to removal of tooth leading to accumulation of blood in that area.
Make your child do warm saline gargles.
The red thing can gradually disappear.
In case if it does not go away you can once consult an Oral Physician and get checked.
However it does not seems to be anything serious.
You can also send pictures of the red fleshy thing to me so that I can advise you better what exactly it is and how it has to be treated.
Hope I have answered your query.
Let me know if I can assist you further.
Regards, Dr. Honey Arora..