Itching with rashes and redness all over the body may indicate an allergic reaction, infection, or skin condition. You should consult a dermatologist for proper evaluation and, in the meantime, avoid scratching, use gentle skin care, and keep the skin moisturised.

Allegra 120 (Fexofenadine) is an antihistamine and can help relieve runny nose, sneezing, or allergy-related symptoms, but it will not reduce fever or headache from a cold. Since your cold has lasted 8 to 9 days with fever and headache, it is best to see a doctor.