My son 11 years old was suffering from viral fever, for 5 days, the 6th day fever was normal but he started having pain in his lowers back gums at both side, then after three days gums were normal. But after 15 days still he gets oral temperature 99.3 in the evening time. We did all the tests typhoid, dengue, chicken gunja, malaria Ana, every thing was negative. Can anybody help us to understand why he gets temperature 99.3 at evening that goes off without any medication by around 9.30. Pm.