I hope you are doing under doctors advice. If not, Please see the doctor immediately

Yes you can give steam if no fever. It works well in nose blockage.

If mild,avoid unnecessary medicine and just give steam inhalations for cold and cough and decongestant nasal drops for nasal block or increased cough on lying down. Use paracetamol for fever and repeat every 4 hours if required. If not improving OR accompanied by other symptoms like wheezing or breathlessness or dullness and refusal to feed,consult your paediatrician asap.