This information is taken from Seambiance.com:
Lavender is the most versatile of essential oils. It is relaxing and refreshing, uplifts the spirits, and helps to relieve the distress of muscle pain. Your home should be without it. Balances your body and mind. Calms or stimulates according to your bodies needs. Excellent for refreshing tired muscles, feet and head. Add a drop to the pillow sheet before peaceful sleep. Treats burns and reduces scaring. Can be used neat in small amounts on burns, but care still needs to be taken. Traditional uses are muscle relaxant, soothing agent, skin conditioner, and astringent. Lavender blends well with bergamot, clove, rosemary, eucalyptus, patchouli, clary sage, rose, and jasmine. Linalol is a active component of Lavender that is therapeutically beneficial.
From the above description, Lavender oil is not useful for creating a barrier to prevent bacteria from getting into a fresh piercing. This is the only purpose for the antibiotic ointment being used at our shop.