Hello! I have been through your question. According your concern i think that you should know that young children usually have few symptoms, and the infection often goes unrecognized but it is important to be careful of certain complications such as an enlarged spleen, hepatitis, anemia,myocarditis, meningitis, encephalitis and Guillain-Barre syndrome .What I suggest for your son is to meet as soon as possible an Infectious Disease Specialist to do a physical examination in order to exclude an complication involving nervous system(related mostly with your son symptoms). During this time he should rest and take a lot of fluids, good nutrition, because these are the key of recovery. I hope my answer help you. I wish a quick recovery.