Thanks for writing to health care magic.
Where did he have this abscess?
Was it after vaccination
or after a boil?
Did he have any fever?
Is he on some antibiotics?
Is he accepting feed normally and active?
If he is not accepting feeds or having high grade fever or he is vomiting
then you should go to the doctor immediately.
If the induration is not decreasing or swelling is increasing you should consult your doctor.
Hope this helps.