If your 5-year-old daughter's eyelid is swollen after being bitten by a mosquito, you can continue applying ice to reduce the swelling and pain. Make sure to clean the bite area with water and soap and avoid scratching to prevent bacterial infection. You can also give her Benadryl™ to help with itching and swelling, but it may cause drowsiness. If the swelling worsens despite treatment or if signs of infection appear, it is important to see a doctor. In case of severe allergic reactions, such as difficulty breathing or palpitations, seek emergency medical help immediately.