If someone has lymphoma and have recurrent fevers. would it be like 99.0-99.0 or above 100.4 ? what's concerning? and if 99.5 occurred with nodes

Life is not exact: Life is not exact. A person at home can measure his temperature in whole numbers. Thermometers are not exact. Human bodies are not exact. So, if one is wondering what to tell the doctor, just use whole numbers. Also, every person is different, so "recurrent fevers" can vary from time to time in one person, and vary among different people. There is no exact number. A couple of doctors can evaluate.

Usually >=100.5: Temp has to be taken in context. Even low grade (<101) is important if it accompanies other symptoms such as sweats, chills, malaise, cough or other things. If your talking about a temp in the diagnosis of lymphoma, it's usually high fevers (ie 102, 103) and may not have other symptoms except sweats when the fever breaks.