"I am not a meth head," he told ET's Jennifer Peros, slamming reports that claim he's become heavily into drugs over the years. "I have never touched it in my life."
Carter told ET he has hiatal hernia, a condition in which part of the stomach pushes up through the diaphragm muscle. He's suffered from the abnormality since he was 19 years old, about seven years after his hit, "I Want Candy," was released.
"I have a stress condition of an 80-year-old man," he explained. "I am also lactose intolerant."
The Tampa, Florida, native told ET that he's dropped approximately 20 pounds since he was first diagnosed with the hiatal hernia.
"[I weigh] 135, 140," he said. "Yeah, and I'm 5'8. [Doctors] said avoid stress. Because I can develop cancer."
Carter is well aware that up until this point, many of his fans didn't know about his battle with the disorder, but he admits the struggle goes far beyond the disorder itself -- he says it's troubling to even look at himself in the mirror.
"Oh my God, it hurts so badly," he said. "It hurts so badly because there's like nothing I can do about it."
Doctors have told Carter to "avoid stressful situations," which has prompted him to deactivate his social media accounts every once in awhile due to all the negative comments he receives. He said he does read what people write, but tries to "have love" in his heart for them -- even the cyber bullies who tell him to "die" or constantly ask him to explain the reason behind his looks.
"How would you feel every two seconds, seeing a tweet, 'You have AIDS. Go die. Oh, look at this meth head. Oh, meth kills. Crack kills,'" he asked. "It's body shaming and it’s the toughest thing to deal with."
Things took an extra emotional turn when ET then asked Carter, "What's one thing you want to say to all the nasty fans out there?"
"I… I'm sorry," he said, as tears erupted. "I am sorry for the way that I look."
"I am going to a training camp called D1 Combine Training and I'm going to transform my body. And get healthy," he revealed. "Hopefully tomorrow. We're already working on it, I've been asking for a year."
"To everybody I say, 'Give me a break so I can look better, so I can eat,'" he urged.
Carter continued on, telling ET that in addition to the disorder, he gets Voluma fillers to "fill my face."
"It's just how I'm built. This is how I look," he explained, admitting he uses JUVÉDERM and Restylane treatments. "If you look at my grandpa Carter, if you look at Douglas Spalding, my grandpa, he was a track runner."
"Unless you're in my body, you don't know. I mean, look at that," he said, lifting his shirt to reveal his abs. "I have an eight-pack."
Despite his constant struggles, Carter said he has found a positive in all of this.
"To keep it 100 percent with you, there are so many other guys out there that have been reaching out to me on Twitter that have said, 'Thank you so much Aaron, you're the first man that stepped up about weight issues,'" he explained. "I'm actually becoming a voice for people who are going through this."
"You don't [see it a lot with male celebrities] but it does happen. A lot more," he continued. "The difference is, men are a lot more prideful. We don't want to admit it. I don't want to admit I don't look good."