The teen was riding his bike around 6 p.m. on Aug. 12 near 177 Myrtle Ave. when he got into a fight with an unidentified person, according to a police report.
The altercation became physical and the suspect pulled out a box cutter, slashing him in the neck, chest and back, police said.
The boy took himself to Brooklyn Hospital where he was treated, police said.
No arrests have been made.
Other notable crimes from Fort Greene and Clinton Hill, according to police, include:
► A 55-year-old man was arrested for hitting an 84-year-old man with a stick near the corner of Park and Grand avenues around 7 a.m. on Aug. 8. The victim received a laceration on the left arm but refused medical attention.
► A 33-year-old woman’s wallet and phone were stolen as she was sitting at a bus stop at 152 Vanderbilt Ave. around 9:35 a.m. on Aug. 9.
► A 50-year-old woman was slapped in the face around 2:10 a.m. on Aug. 10 as she was standing near the corner of Myrtle Avenue and Adelphi Street. The woman fell to the ground and the suspect stole $10 in cash. She was taken to Brooklyn Hospital with swelling and bruising.
► A 49-year-old woman’s phone and driver’s license were stolen by two unidentified suspects as she was walking to the train station near Fort Greene Park by the corner of St. Edwards Street and Willoughby Avenue around 9:10 a.m. on Aug. 10.
► A 43-year-old man’s electric bike, worth $1,700, was stolen as he was making a delivery at 11 Putnam Ave. around 5:30 p.m. on Aug. 10.
► A 35-year-old woman was walking to get ice cream near Willoughby and Clermont avenues when an unidentified suspect asked her for the time, then snatched her phone, around 9:30 p.m. on Aug. 10.