Exercise caution while using essential oils. Make sure to dilute them in
a carrier oil. Tea tree oil may be used without a carrier oil at the site of
infection.

Cedarwood:

good for acne conditions and oily skin

Clary Sage:

aids excessive sebum (oil) production and helps reduce
inflammation

Geranium:

has a balancing effect on sebaceous (oil) glands

Lavender:

effective regenerative oil, antibiotic and antiseptic. It
promotes the prevention of scarring

Sandalwood:

is a very soothing and strengthening oil, contains
antiseptic properties to help control bacteria, it is excellent for acne,
and works to reduce excessive sebum production

Tea Tree:

a powerful antibacterial and antiseptic, good for acne
conditions

Ylang Ylang:

helps balance sebum secretion, useful for toning
excessively oily skin.

You can combine the above essential oils with other oils that are
beneficial to oily skin such as

Bergamot, chamomile (has anti- inflammatory properties), grapefruit
(great for congested skin), lemon, lemongrass, mandarin, petitgrain,
and violet.

Grapeseed oil is a great carrier (base) oil for oily skin.

Add some carrot oil, which helps reducing scaring and inflammation.
It is also rich in vitamins A, B, C, D and E. You only need a small
amount of carrot oil, so add it as part of your carrier oil (using too
much over a long period can cause skin discoloration due to its natural
orange pigment).

Jojoba oil also works wonders for oily skin. It protects and moisturizes
oily skin while it helps to balance sebum (oil) production. Jojoba
makes a wonderful base oil for combination skin as well.