<s>[INST] I applied parsley oil to my upper gum in my mouth to help sensitivity from tooth.  My left side of my mouth,top an bottom immediately went numb.  It has continued to get numb on and off as well as my tongue and my left hand from which I applied the oil.  I am applying heat to the area an it helps the numbness go away.  Should I go to Dr. [/INST] Thanks for your query, I have gone through your query. The parsley oil will not help you to reduce the sensitivity in the teeth. The numbness can be secondary to allergic reaction to the oil. Nothing to be panic, consult an oral physician and get it evaluated. For the sensitivity, you can use desensitizing toothpaste like strontium chloride, potassium chloride(sensor toothpaste) or fluoride containing toothpastes. If it is secondary to the decayed teeth then the teeth has to be restored with a cement material. I hope my answer will help you, take care. </s>