What Causes Recurrent Fever In A Toddler?

My daughter is of 3 yrs 2 months old. she is getting fever often. Last week of July she was down with viral fever. then 2 weeks back, she again got fever with 102 F. I gave Pacimol - 3.5 ml that night. Then her temp did not raise and it got settled within that night. Again on last Friday, she was very normal. at 2 o clk, her temp was 100, it started to raise till 102. then I gave pacimol - 2.5 ml. for the past 2 days, she is having the temp like 100.8,100.9. during night, it goes till 102. if I give pacimol, temp wont raise. Today morning, temp was 99.6. why she is getting fever often? will there be any other problems.