I'm sorry to hear that you're experiencing fever, body pain, and now red rashes with itching. These symptoms could indicate an allergic reaction, an infection, or another medical condition that needs prompt evaluation.

Here are some important steps you should take:

• Seek medical attention promptly: A doctor, preferably a dermatologist or an infectious disease specialist, can examine the rash and assess your overall condition to determine the cause.
• Avoid scratching the rash: This can worsen irritation or lead to infection.
• Note any other symptoms: Such as difficulty breathing, swelling, or worsening fever, which would require emergency care immediately.
• Do not self-medicate without guidance: While antihistamines like fexofenadine (found in Allegra) can help with allergic itching, it is important to confirm the diagnosis before starting treatment.

If symptoms worsen rapidly or you develop breathing difficulties, call emergency services immediately.

Please consult a doctor as soon as possible to get an accurate diagnosis and appropriate treatment.To narrow down potential causes, we will need some more information.I understand that you have been experiencing fever and body pain for the past 3-4 days, and now you have developed red rashes and itching. Please tell me your age and gender.