Your symptoms, such as a blocked nose, mild fever, dry mouth, and slight throat pain, usually happen with a common viral cold or sinus congestion. When the nose is blocked, you tend to breathe through your mouth, which makes the mouth dry and can also irritate the throat. Mild fever often means your body is fighting an infection, and in most cases, this improves on its own in a few days. Try resting well, drinking warm fluids enough, and taking steam inhalation to clear the nose. Warm saltwater gargles can ease throat discomfort. Avoid cold drinks, dust, and very spicy food for now, as they can make irritation worse. If the fever goes higher, symptoms last more than a week, or you get facial pain, thick yellow-green nasal discharge, or breathing trouble, then it could be a sinus infection, and you should get checked by a doctor.