To help your 4-month-old with their cold and cough, you can stop giving them Tempra™ since they don't have a fever. You can try using the technique from Ste-Justine Hospital (a mixture of water, salt, and a syringe without a needle) to clear their nasal passages. This should help reduce mucus buildup and relieve their symptoms in a few days. Stay well-hydrated, keep the air moist, and give your child plenty of rest to help them recover more quickly.