Thank you for your query.
What you describe seems to be an abscess
formation which must be painful. Local Neosporin
is not going to act. I suggest you consult your doctor and get it drained so that the pus is removed. He will require systemic antibiotic to take care and shall take at least three to four days to dry up.
I hope I have answered your query to your satisfaction.
Wishing your son an early recovery.
Rajiv K Khandelwal