A cough lasting 7 days and getting worse needs proper evaluation, especially in a child, and since Deriphyllin Syrup has not helped, it may not be the right treatment for the cause (such as viral infection, allergy, asthma, or sometimes a bacterial infection), so it is important to have your child examined by a pediatrician who can listen to the chest and decide if any other medicines like inhalers, anti-allergy treatment, or antibiotics (only if needed) are required. Meanwhile, ensure your child drinks plenty of fluids, gets adequate rest, and avoid giving over-the-counter cough medicines without medical advice. Seek urgent care if there is a fever, fast breathing, wheezing, or difficulty in breathing.