Blot at the stain with a clean white cloth to absorb excess oil. Do not wipe at the stain; you will just spread the oil over more of the dress.
Apply a stain stick or store-bought solvent-based stain removal agent to the stain. Follow the directions on the container for proper use. If unavailable, then apply a heavy-duty liquid laundry detergent to the stain, and rub the detergent into the dress. If satin or silk, apply to an area along the inside seam to test for material discoloration.
Wash the dress per the instructions on the tag. If the dress is satin or silk, then you may have to take it to a dry cleaner for complete removal of the stain.