Thank you for your query on Healthcare Magic.
This spectrum of puffy swollen neck and jawline and complaining of lump in the base of throat are due to enlargement of lymph
nodes and lymphoid tissue which is classically seen in mono in the second week after 1 to 2 weeks of a prodrome of fever
This swelling is not normal and because of this swelling there may be obstruction to breathing if it increases further.
The pain in splenic area is due to enlargement of spleen
Avoid contact sports and play as to prevent injuries which may cause injury
to enlarged spleen.
Therefore I advise you to consult ER or your Pediatrician
as early as possible to assess the throat and to look for any impending respiratory obstruction.
Hope I have answered your query.