Hi thanks for writing to Practo consult
As the baby is small please consult pediatrician.
Meanwhile you can start nasal saline drops, and increase fluid intake by baby to 3-4 glasses. Watch for fever.
Next Steps
Do read this article of mine
"Common Cold: Its Very Common, Don't Panic" by Dr. Poonam.M. Sambhaji - https://www.practo.com/healthfeed/common-cold-its-very-common-don-t-panic-8682/post