The former EastEnders actor is said to have had facial reconstructive surgery after he crashed his Mini Cooper into a steel barrier in Derby on January 30.
Speaking to Aled Jones and Lorraine Kelly on ITV's Daybreak, Gaffney stated that he hoped to warn others to make sure they are buckled up, while also revealing a scar on his face.
"I know I'm a naughty boy and it takes something like this – I always learn the hard way in my life," he said.
"I was pulling out the theatre I was working in on a play, an Agatha Christie play, and I was pulling out of the theatre and I was reversing and then I just completely forgot and then drove on my merry way and 20 minutes later this happened.
"There's so many different things that could have happened that made me not walk away from it, to be honest."
He continued: "I was trapped inside. It reads worse than it actually was. I mean the fact that I didn't have the seatbelt on – the paramedics and the hospital staff at Derby Royal Hospital I have to say were brilliant, the NHS really looked after me and I want to say thank you to those guys – and they said that had I been wearing a seatbelt I probably would have just got whiplash and I would have walked away with none of this.
"It could have been a lot worse. One inch down and I would have been blind, and one inch up I would have been brain damaged. So there's so many things that could have gone wrong and the fact that I'm able to walk away and obviously you've got this campaign with the seatbelt thing, it's so important – I can't stress that enough."
Gaffney thanked those who gave him messages of support while he was in hospital, saying: "The amazing thing to be honest that's come from all this is just the well wishers.
"I mean the text messages from people from EastEnders, cast members and producers and whatnot, and people from everyday life that I've worked with along the years have just been so amazing that every text that comes through is from someone that really cares."
On his future plans, he added: "I'm going back to A Murder Is Announced tomorrow, which is in Stevenage, an Agatha Christie play that I'm doing. I'll be fine. And then I'm going on to do Let's Dance for Comic Relief, so I've been quite busy this month, which is nice.
"The nicest thing is at the moment I'm off the painkillers so I'm alright at the moment, I'm very lucky."
Gaffney previously called himself "an idiot" for not wearing a seatbelt prior to the accident.