Arron Kmiotek attacked the 19-year-old after it was claimed he was friends with the culprit.
He walked over to the teenager - who he knew from school - and smashed an empty pint glass in his face, causing deep lacerations to his cheek, nose and right upper eyelid.
He was treated by specialist surgeons for his wounds which needed 30 stitches. Doctors told him he would be scarred for life.
Nottingham Crown Court heard the attack happened at a social club in Bircotes on 23 November 2018.
Kmiotek’s girlfriend turned up and accused a man of distributing topless images of her without her permission. The court heard the images were obtained when Kmiotek’s mobile phone was hacked by work colleagues.
The girlfriend threw a glass of lager over the man. In a bid to diffuse the situation, bar staff asked the man to leave.
The 19-year-old asked the bar staff to explain why the girlfriend had not been asked to leave instead, as she had been the aggressor.
Moments later, he was attacked by Kmiotek.
Police were called and he was arrested. At court, the now 23-year-old, of Mirabelle Way, Harworth, pleaded guilty to wounding with intent to cause grievous bodily harm.
He was jailed for two-and-a-half years. He will serve half the sentence in prison and the other half on license.
Following the sentencing, Detective Constable Michael Booth, who led the investigation, said: “The was a cowardly attack and it is lucky the victim is not blind as a result of Kmiotek’s inexcusable actions. He will, however, have to carry the scars of this totally unprovoked assault for the rest of his life.
“I am pleased that justice has been done and hope this sentencing will bring some degree of relief to the victim.
“I also think this case should serve as a warning to other people about the serious consequences to being a perpetrator of violence.
“Kmiotek’s actions were entirely unacceptable and such behaviour will never be tolerated in Nottinghamshire.”