Scott, 31, of Penistone, suffered a knockdown in the final round and collapsed in his changing room after the fight. He was taken to hospital and his promoter, Stefy Bull, confirmed his death on Monday.
Jerome, 33, who was left in a coma for 10 days after being injured in the ring himself three years ago, was in the crowd at The Dome in Doncaster to support his former training partner Curtis Woodhouse.
Jerome, of Arbourthorne, spent eight weeks in hospital following a fight against Serge Ambomo in September 2014.
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The dad-of-two was at The Dome in Doncaster on Saturday with his brother, celebrating his 33rd birthday and to support Curtis, who was due to fight later in the evening.
He said: "I knew just watching the fight it was serious. I had a feeling it was severe because of how he was having to be supported.
"I spoke to my brother and said something wasn't right. I got up and went to see Curtis before he was due to go out and fight and Scott was walking into the changing rooms.
"I was speaking to a lot of people and said there was something not right - it was horrible I saw him getting stretchered out."
Scott, who was trained by Glyn Rhodes at Sheffield Boxing Centre, won the English title eliminator against Dec Spelman and conducted post-fight interviews before falling ill in the dressing room.
He died in Royal Hallamshire Hospital over the weekend.
Jerome added: "You never think that something bad is going to happen until it happens to you. It's always in the back of your mind but, as a boxer, you have got to prepare your mind and body and you do whatever you have to do to achieve that.
"I have a love-hate relationship with boxing ever since it happened to myself. I have always been a bit wary of boxing, I've always needed a reason to attend boxing. I will go to support somebody or a friend, like I did on Saturday for Curtis, but I don't go for entertainment."
Jerome said he didn't know Scott personally but added he had a good relationship with his trainer Glyn Rhodes, who rushed into the ring to help him during the bout at iceSheffield in 2014.
He said: "I messaged Glyn asking how Scott was and he said he was waiting in the same room as they were when I was in hospital, which really brought it home.
"Glyn rushed into the ring and put me in the recovery position and did his best to help me so I have a lot of respect for him - he helped me in my time of need."
Jerome said his thoughts were with Scott's family and friends and said 'they must remember the good times' they had together.
"They have lost their son, their brother and someone who they loved and hopefully they experienced good memories," he added.
"They should cherish those memories that they have got together and hopefully find the strength to carry on. They need to just try and keep strong that's exactly what Scott was.
"He was a warrior who fought right to end and showed great pride."
Scott, who was trained in Sheffield by Glyn Rhodes and lived in Penistone but is originally from the North East, only started boxing at the age of 24.
Speaking to Boxing Social in his post-fight interview, he said: "I will box anyone. I do it for the fun not because I think I am going to be world class fighter - I just do it for purely for entertainment and I am just glad we could put on a show and keep everyone entertained."
Scott, a former ski instructor, worked as a chef at Sheffield's Royal Victoria Holiday Inn and his victory over Spelman meant he was one win away from becoming the English light heavyweight champion.
Mr Rhodes, thanked the boxing community for its support in a post on the SBC Facebook page.
In a post on the centre's Facebook page, he said: "From all at Sheffield boxing centre., today our hearts are broken as we have to share the devastating news that one of our ‘family’ has sadly passed away over the weekend whilst pursuing his dreams.
"Our only thoughts are with his immediate family and friends at this time. Scott truly was a member of the SBC unit and from the ‘babies’ to the old timers was loved by everyone.
"The heartfelt messages of love and support are greatly appreciated and a comfort at this time. Goodnight, God bless champ."
A fundraising page has been set up to support Scott's family. Visit https://www.gofundme.com/scott-westgarth to donate.