The 'Lullaby' hitmaker fell "face down" into steel and concrete after convulsing for eight minutes while on his own at home in April and he has been "clawing [his] way back" to health ever since.
He revealed on Instagram: "I had a grand mal seizure while home alone, fell face down into steel and concrete and convulsed for 8 minutes, repeatedly hitting my head and face - I've never watched the CCTV.
"The bruising internally was more the issue and I've been clawing my way back ever since.(sic)"
The 38-year-old rapper - whose real name is Stephen Manderson - explained he had a seizure because he hadn't been looking after himself properly.
He continued: "It was caused by a culmination of things, but largely I'd not been taking care of myself, the opposite in fact.
"I nearly lost my family, my family then nearly lost me."
And Green urged others to "deal with" their health.
He added: "If you don't, it'll deal with you."
The 'I Need You Tonight' performer - who has 22-month-old son Slimane with partner Karima McAdams - previously had to cancel a tour in 2019 after fracturing three vertebrae in his neck during a seizure and vowed at the time to look after himself better.
Posting about the incident at the time, he said: "Just after I sent this pic I sent to someone to say how ready for tour I was, I had the first seizure I've ever had which led to me falling without hands to soften the fall and fractured my neck in doing so.
"After I got to the hospital I had a second seizure with again no obvious cause.
"There's one theory - I've run myself into the ground doing way too much, over-stretching myself as per usual and it's finally caught up on me.
"Seems quite likely. I'm gonna use this time to implement all the self-care I encourage others to put into practice - and it's going to stay in practice as there's nothing like nearly breaking your neck to put things into perspective.
"Rest, studio, books, and efforts into building what might even be a relationship... A healthy one. Not one based on toxicity. Crazy, I know."
Tagged in Professor Green