3 1/2 year old sick with fever over 3 weeks now-now seems like it is starting all over again! Help please...My 3 year old has been sick since Sat. Jan 8th. It started out just like a cold-with sniffles and congestion and fever. So, we treated it with Motrin (switching off with Tylenol ). During the week, the cold seemed to be getting much betthe. Then, that following Friday afternoon (6 days later) out of nowhere she started getting really congested all over again, had a stomachache and suddenly spiked a fever of around 105. Her pediatrician at first said it was the flu virus, but they have not been able to confirm this with swab tests. Between the second and third week of this, she had about 5 days of watery diarrhea . Since then, she has developed fever blisters outside and inside her mouth( her poor lips are splits and bleeding) and the fever has been ongoing (hovering around 100-101). She has been back to her pediatrician several times and they recently did a test for all known viruses that just came back negative! What is this? I appreciate any ideas you might have.