Suggest Treatment For Viral Infection And Cough In A Child

Hello Doctor My son had cough which followed a mild viral infection of HFMD. for past couple of days he has very severe cough and sometimes vomit due to that. we are trying steam and vicks but its getting worse and he keep crying and coughing in the night. he has lot of mucous as well. so far giving Tminic but its not helping with cough at all. can you advise if i can give relent as he is not able to sleep in night and so are we