A Fifth Avenue plastic surgeon turned a glamorous model into a “sex slave,” subjecting her to sickening abuse — and tried to cover up her black eye by injecting her with filler without anesthetic, an explosive new lawsuit claims. Ammar Mahmoud, 40, at one point allegedly beat his ex-girlfriend Maya Willow Sias, 25, so savagely he shattered her eye socket, according to the $10 million suit filed Tuesday. Sias alleged that Mahmoud secretly then took her to his Alinea Medical Spa, where he injected fillers around her still-swollen eye — a tortuous procedure he did with no anesthetic, the suit states.

“He stabbed me in the face with a needle, I could feel the needle scratching against the bone,” Sias told The Post in an exclusive interview. The Los Angeles-based singer and model, who once appeared in “Maxim,” contends in the Manhattan Supreme Court suit that Mahmoud is a violent drug- and alcohol-abusing sex addict hiding behind the facade of a caring plastic surgeon. She also believes Mahmoud has allegedly beaten and abused other women — an accusation echoed in an ongoing 2014 lawsuit filed by the doctor’s ex-wife.

Sias documented the bruises and other injuries she allegedly received at Mahmoud’s hands during their nine-month relationship in stomach-turning photos littered throughout the 16-page civil complaint. “There is no ‘she said’ here,” her attorney Larry Hutcher, a partner at Davidoff Hutcher & Citron LLP, told The Post. “He literally made .