If your child is still experiencing a fever despite taking Tylenol, you can try alternating between Tylenol and Advil as recommended by a healthcare professional. Make sure to carefully monitor your child's symptoms and general condition. If their situation worsens, don't hesitate to contact public health authorities, especially in light of the current Covid-19 situation. If you have any further questions or concerns, feel free to reach out for assistance. Have a wonderful day!