Jeremiah Sewell, 19, was attacked when he was in a parked car at 4:40 am on Saturdays in historic Beckenham Place Park, the largest green space in Lewisham.
Police were called ten minutes later when Jeremiah, from Bellingham, checked himself into a hospital in South London.
There he later died of his horrific neck injury.
Detectives have launched a murder investigation and his family continues to be supported by specially trained officers.
Police arrested two men aged 18 and 19 on suspicion of murder overnight and into the early hours of Sunday.
Two other men, aged 21 and 26, were arrested on suspicion of aiding an assailant.
All four are still in custody at the police station.
Chief Inspector Chris Wood, who led the investigation, said: “My thoughts are with Jeremiah’s family and friends.
Detectives have launched a murder investigation
/ Getty Images“Jeremiah’s family deserves answers about what happened to him and who was responsible for his death.
“We are working hard to provide those answers and while our research has progressed significantly, we still need members of the public to come forward and tell us what they know.
“Your information could be vital to our investigation, no matter how insignificant you think it is. Contact the police or Crimestoppers with everything you know.”
Anyone with information is requested to contact police on 101, quoting CAD 1368/16Jul, or Anonymous Crimestoppers on 0800 555 111.