Yes coconut oil is good for a cold sore.
The coconut oil when applied to the cold sore a few times per day can help get rid of the cold sore within 4 days or sooner.
The coconut oil works to get rid of cold sores because the coconut oil contains antiviral, antiseptic, and anti-inflammatory properties.
Those antiviral, antiseptic, and anti-inflammatory properties of coconut oil are what helps get rid of the cold sore faster.
You can also apply some toothpaste or apple cider vinegar to the cold sore which helps the cold sore go away much sooner.
There's no cure for cold sores but using the above mentioned things can help the cold sore go away faster.
Applying some ice can also sometimes help a cold sore go away as well.