A Queens woman allegedly pretended to be a doctor and performed a butt-lift operation on a patient, who became seriously ill after the operation, cops said.

The 40-year-old victim paid suspect Liliana Coello $2,500 for a rounder derriere and underwent a procedure at Coello’s 157th Street home on Nov. 3, sources aid.

Several days later, the woman’s backside became infected, and she ended up in the hospital, sources said.

Coello was slapped with charges of assault, reckless endangerment and unauthorized practice of a profession, sources said. Cops said they confiscated her tools and charged her with criminal possession of a weapon.