Thank you for your query on Healthcare Magic,
As the lymphnodes
enlarged and CBC showing infection one course of antibiotic to be given and after the completion of antibiotic therapy the size of the lymphnode to be assessed.
If the size is decreased, it is due to a bacterial infection and no further evaluation is required.
If the size remains same or increasing other investigations like FNAC of the lymphnode to be done to know the nature of lymphnode enlargement.
Hope I have answered your query.