A 19-year-old was fatally stabbed in Brooklyn just blocks from his home, police said Wednesday.

Mortally wounded Mamadou Bah staggered into Gentlemen’s Quarters Salon at 1916 Church Ave. in Prospect Park South around 10 p.m. Tuesday and asked for employees to call an ambulance –– complaining of stomach pains, police said.

An employee called the police and claimed the teen, who assured him he was “fine,” was having trouble breathing –– but soon realized he was bleeding from his torso, police said.

A worker discovered a wound under his left armpit and called police, authorities said.

Bah was taken to NYC Health and Hospitals/King County, where he died.

Police did not recover any weapon at the scene.