I love essential oils. I love them so much I respect them. Please ensure you are using Pure Essential Oils.  Cheap is not necessarily cheap. My do Terra Oils are so pure, you only need a small amount to receive a wonderful benefits.
Carrier Oils such as Fractionated Coconut oil will dilute an essential oil and slow down its rate of absorption if there should be any discomfort or skin irritation.
 Not sure about dilution ratios? There are several dilution charts available  I have available. I do suggest diluting all oils.
 People with sensitive skin can use a patch test to determine if they would react to particular oil. It is generally safe to apply essential oils to the soles of the feet even for people with sensitive skin.

 Essential oils rich in phenols (the hot oils) should be used with caution when applying to the skin. Use caution when applying to any sensitive areas, such as the throat and face.  
Always keep essential oils out of the reach of children.
 
 Pregnant women should consult their healthcare professional before using essential oils.

 Keep essential oils away from the eye area where even the vapors can cause irritation.
 Do not handle contact lenses or rub the eyes with essential oils on your fingers.
 Oils with high phenol content can damage lenses and irritate eyes. If essential oils accidentally get in the eyes, pour carrier oil in the eyes to stop the burning.
Don’t use water. Water will drive the oils in faster increasing the burning sensation.

 Essential oils may be applied on or around the ears, but don’t pour essential oils directly into the ears.

 People with epilepsy, high blood pressure, or who are prone to convulsions should consult a healthcare professional before using essential oils. Hyssop, fennel, and wild tansy oils should probably be avoided in these cases.