Diagnosed with influenza b thursday. had a fever (99-102) since tuesday. fever won't go away. should i be worried?

No: The febrile phase of influenza B can last 7 days (sucks big time, doesn't it). Make sure to keep yourself well hydrated. If temp is going over 104 or you develop worsening cough and/or shortness of breath, seek medical care again as you can develop a secondary pneumonia. In the future, to avoid this, get flu vaccine EVERY YEAR! Hope you feel better soon.