The victim, 24, was assaulted on Shoreham Street, Sheffield at around 3am on October 15.
She was walking along the street with a friend when a man punched her in the face after verbally threatening her friend.
The woman suffered serious injuries to her lip and face from the attack and was taken to hospital.
And doctors today said they now believe her injuries may have been caused by a knife.
Police have released CCTV footage of the incident.
Anyone with information is asked to contact police on 101.