A complete sinus blockage with blood in your phlegm requires prompt evaluation by a doctor to rule out serious underlying causes. Surgery might be needed if medicines fail to clear the blockage or if there is a large polyp or other structural issue. Your doctor will decide after a thorough examination and any further tests.

Since your symptoms have persisted for 10 days despite taking Nam Cold SR, you should consult a doctor rather than self-medicating. A prolonged cold can lead to secondary bacterial infections, bronchitis, or sinusitis, which require specific prescription treatments like antibiotics or targeted cough formulations. Please stop Nam Cold SR if it is not providing relief. In the meantime, stay well-hydrated, practice steam inhalation, and get adequate rest. A physician needs to examine your chest to prescribe the correct medication, such as an expectorant or bronchodilator, based on whether your cough is dry or productive.