The 42-year-old former Atomic Kitten singer had her third round of surgery to reduce her breasts earlier this summer, taking them down from bra size E cup to a C cup and combined with an 'uplift'.
But she has since suffered swelling that has made her uncomfortable and even affected her breathing.
Katona wrote in he column in New magazine: "I'm really swollen and it hasn't got any better. I ended up going to A&E as I was so worried about it.
"They've told me that they need to investigate further. So for now, my doctor at Pall Mall Cosmetics has given me some water tablets which will hopefully help with the swelling."
The former I'm A Celebrity... Get Me Out Of Here! winner had previously described the complications she was suffering as causing a tight chest that made it difficult to breathe.
She said: "I was lying down in bed and I felt like I couldn’t breathe.
"My throat and chest felt really tight, it was awful. I felt like I was going to die."
"My body has been swollen since I had surgery last year. My whole body is sore and puffy – my legs, my stomach, my face, my neck. I feel like I need popping."
Watch: Kerry Katona shares video from hospital bed after surgery
The mother-of-five said: "I am going to be having a breast reduction because these bad boys, as much money as they're making me money on OnlyFans, are doing my b****y head in. They're far too big, they give me lots of back ache.
"And every time I put a jumper on, I feel like, you know the Honey Monster on the Sugar Puff advert? That's what I feel like!
"So I'm getting a reduction today and I'm very, very excited but I'm also really, really nervous."
Katona shared footage of herself talking to the surgeon before the procedure, and told him: "The main reason I am doing this is because of my back."
The singer is also mother to daughters Molly, 21, and Lilly, 19, from her marriage to Brian McFadden, as well as daughter Heidi, 15, and son Max, 14, from her second marriage to Mark Croft.
Katona is engaged to personal trainer Ryan Mahoney, who she met on dating app Bumble in 2018. He proposed in August 2020.