Karamo Brown is opening up about a painful plastic surgery ordeal for the first time -- after years of fans speculating about changes to his appearance.

The "Queer Eye" star revealed he underwent buccal fat removal in 2021 after gaining 70 pounds during the pandemic ... but says the procedure left him with chronic pain caused by scar tissue that blocked his saliva glands.

Karamo said the buildup made it painful to smile and left his cheeks swollen with saliva and scar tissue -- a problem that became even harder to manage while filming his now-canceled daytime talk show he had launched back in 2022.

He told PEOPLE he had since undergone corrective surgery to repair the damage and remove the scar tissue, and also opted for a lower blepharoplasty while he was at it.

Looking back, Karamo says he stayed quiet for years because he was embarrassed by what happened ... and never even pursued legal action against the doctor who performed the original procedure.

The revelation comes after a turbulent stretch for Karamo -- we reported on the drama surrounding his tumultuous exit from "Queer Eye's" 10th and final season.