Based on the history and clinical picture, it seems to be either Acute Lymphadenitis or Abscess. Tubercular origin is less likely if the duration of symptoms is acute.
Next Steps
1) Kindly undergo Ultrasonography of Neck to confirm the diagnosis.
2) If it comes out to be Lymphadenitis, look for any flu symptoms like cough, cold or fever & take an antibiotic course.
3) If it comes out to be abscess, undergo Incision & Drainage. And send the pus for AFB, culture & Sensitivity and treat with appropriate antibiotics accordingly