Suggest Cure For Swelling On The Neck Which Is Gradually Spreading All Over The Body

Hi,my name is Wilberforce,my son David woke up 3 days ago with some swellings on the neck and this has spread all over the whole body.The swellings go down at night but come back again during the day with very high fever..took him to the hospital and they gave him cetrizin +ibuprofen bt it hasn't worked..took him back they did a urine test and said it is UTI so they gave him cephalexin and metronidazole but stil no change what could this be?