R.F.
When my son is sick we cut out all milk and sugars and up the amount of water and 100% juices and make sure we are keeping his hands extra clean (we usually do but everyone washes after every sneeze and cough while he is sick) and put a vaporizer in his room while he sleeps, I like the plug-in kind that need no water.
If it is just a slight fever and there is no coughing and no color in the mucus coming out of her nose it might just be an irritant in the air and that might just need the vaporizer and less AC and/or fans while she sleeps.