Frankincense (Boswellia carteri) can be used as an edible in small amounts, applied to the skin or burned. It has anti-inflammatory, anti-fungal, astringent, antiseptic, expectorant, carminative, anti-depressant, analgesic, emmenagogue. Frankincense is particularly useful for helping with joint inflammation, repair of the skin, and bronchial issues like asthma. It is highly used in cosmetic. 
To apply frankincense tears on the skin, you can dissolve a small amount in water and use it as a topical treatment. Or you can infuse in oil for topical use. 

It is recommended to use 1/4 teaspoon for a cup of water.