The man targeted the 19-year-old as she went to get food from McDonald's after a night out in Glasgow.
She had earlier spurned his advances in the nearby Frampton's club on Maryhill Road.
Police said five women aged between 19 and 51 suffered irritation to their eyes and skin and were taken to the Western Infirmary as a precaution following the incident at around 2.10am today.
The suspect is described as white, aged between 25 to 35 and had shaven brown hair. He had a scar on the left side of his face running from ear to cheek and wore jeans, a grey cardigan or zip top, a black bodywarmer and black leather gloves.
Detective Sergeant Lesley-Ann McGee said: "The friends had all been out in a local nightclub when the suspect, who was also in the club, made advances towards one of the girls. She wasn't interested and he became abusive and threatening toward her before leaving the premises.
"A while later the party were heading to the nearby restaurant where the attack took place just outside.
"Thankfully, no one was seriously injured, however this was a very frightening thing to happen to those involved.
"At this time we are not aware if the man followed the group to the restaurant or spotted them there on passing.
"Officers are checking CCTV from the club, the restaurant and the surrounding area and there will be additional officers on patrol over the weekend."
Anyone with information is asked to contact police on 101 or Crimestoppers on 0800 555 111.
Police were meanwhile investigating a serious assault on a 20-year-old man in Glasgow's Pollok area.
The victim was in the Priesthill Road and Peat Road area when he was assaulted at around 5.30am.
Officers were speaking to locals today to establish the circumstances of the attack.
Detective Sergeant Jane Drysdale said: "At this time there is no motive and we don't know if there has been more than one assailant.
"I am appealing to anyone who may have been in and around that area around the time of the incident as it's possible you may have seen something which could assist our inquiry and help us find out what has happened to this young man."
In Rutherglen, to the south of Glasgow, a 52-year-old man suffered facial injuries in an assault on Stonelaw Road last night.
The victim was walking near the junction with Greystone Avenue when a small white car pulled up and a man jumped out and attacked him.
Officers have been carrying out door-to-door inquiries and gathering CCTV images to trace the suspect.
Detective Constable David Allan said: "The incident happened around 11.20pm and I would expect a few people to be out and about.
"I am appealing to anyone who was in the area who may have seen something suspicious. Perhaps you saw the white car and can provide further details to the police. I would urge anyone with information to get in touch with us."