Lewis Tavernier, 17, had taken his crossbow to a friend’s house in Stevenage, Hertfordshire, and put the safety catch on before carefully placing it on a nearby desk.
But as the pair chatted, the weapon suddenly and inexplicably discharged and fired into the teenager’s face from less than three feet away - leaving it buried three inches deep into his right cheek.
Lewis Tavernier,17, lies in a hospital bed after accidentally being shot in the face with a crossbow bolt
X-ray shows the eight-inch crossbow bolt lodged three-inches inside his face, but missed crucial nerves
Agony: Lewis suffered a punctured muscle and a fractured cheekbone in the bizarre accident
The A-level student at Marriots School, Stevenage, said: ‘I had used the crossbow lots of times before and I had put the safety catch on so I didn't think twice about putting it down on a desk.
‘But suddenly the crossbow just fired. It was the strangest thing - there was no-one around it and my friend saw it just fire into me.
‘I was only about a metre away but it was so quick and powerful I didn't really feel it go in. I just remember saying; 'mate is there an arrow in my face?'
‘He was really distressed but I guess I was in shock because it didn't hurt at all at first. My friend's dad drove me to hospital and then the pain started.
‘The doctors told me that it was 2mm away from hitting a nerve which would have killed me, and any lower and I would never have been able to talk again.
‘I wasn’t in much pain but I couldn’t believe what had happened, it was so unreal.’
The teenager was rushed to Lister Hospital to have emergency surgery.
The powerful bolt had been shot three inches deep into his face, puncturing a muscle and fracturing his cheekbone.
‘I went into hospital on the Friday night and by Saturday I was back home. I was just a whirlwind,’ Lewis said.
He continued: ‘If it was any lower I wouldn’t have been able to talk again and if it was two millimetres higher I wouldn’t be alive. I was very lucky.
‘I was terrified I was going to lose my eye and I feel so lucky not to be brain damaged.’
Lewis, who lives with his younger brother and his parents Jacqueline and Colin Tavernier, who are both teaching assistants, is recovering well.
But it will take six months to rebuild the muscle in his face, despite only being left with a small scar from the incident.
He added: ‘It aches every now and again but I don’t really notice it.
‘At first I couldn’t open my mouth that much but after that it has been the same as normal.’
The youngster, who is a keen magician, said: ‘I tend to do close-up magic, so things like cards, coins and rope tricks.
‘I’ll definitely be staying away from any medieval weaponry for my acts.’
The friends were originally planning on practising their target shooting in the garden with the loaded crossbow before the accident occurred.