Hi...
fifth disease fever cannot go on like this for 2 weeks. 2 weeks of fever definitely needs evaluation for the cause of fever.
But on important thing - Skin conditions are best diagnosed only after seeing directly. I suggest you to upload photographs of the same on this website, so that I can guide you scientifically.
I have a few questions for you -
1. What is the maximum temperature that you have recorded daily?
2. How is the kid's appetite?
3. What other manifestations does he have apart from this cheek rash?
4. How is the kid's urine output?
5. Are there any joint pains?
6. Is the tongue looking like strawberry?
7. is there any abdominal distension?
Kindly get back with answers to the above questions and also upload an image of the cheek rash and I will be glad to guide you further.
You can approach me at the following link. Please find the link below -
www.healthcaremagic.com/doctors/dr-sumanth-amperayani/67696