Police said the woman, who was bleeding from the mouth, sought help at Coromandel restaurant, which is just off the exit.
Before officers arrived, the boyfriend returned, gave the woman her keys and cellphone, parked the car, which belonged to her, and fled on foot, police said.
Police used Fairfield K-9 Maverick and a Westport K-9 to try to track the boyfriend did not find him, police said.
The woman said she did not want an arrest. She later called to say she had made up the incident, though officers said her injuries were consistent with a blow to the face, police said.
Click here to follow Daily Voice Fairfield and receive free news updates.