Yes baking soda will help get rid of a cold sore and also will get rid of canker sores inside your mouth.
To use baking soda to get rid of cold sores mix some baking soda with some water to form a paste and then apply the baking soda paste to the cold sore and leave the baking soda paste on the cold sore for 10 to 20 minutes then rinse it off.
Apply the baking soda paste to your cold sore 2 to 3 times per day until the cold sore goes away.
You can also get rid of a canker sore using baking soda mixed with a glass of water and then use the baking soda and water mixture to rinse your mouth out and the baking soda will help to heal the canker sore.
Apple Cider Vinegar will also work for both cold sores and canker sores.