Thanks for your query ,I understand your concern.
Well it seems your baby is having a viral infection, along with salivary gland
swelling of one side? Mumps . Nothing to worry as such keep your baby well hydrated , give lots of fluids like plain water, ors water whenever baby is passing motions , butter milk , glucon d water
Give soft diet
avoid sour , cold food in diet, also avoid spicy and oily food. Give paracetamol
in case of fever and some anti allergic like Allegra
Add on a probiotic
also . It's a self limiting disorder donot worry and take a reference from your child specialist too.
I hope I have answered your query ,
Dr Aarti Gupta