It's been reported that B1A4's leader, Jin Young, struggled with enteritis while filming the music video for "Only Learned Bad Things". B1A4's representative stated, "This past June, B1A4 shuttled back and forth between Kangnam and a studio in Kyungki-Do in order to shoot their music video. Despite his high fever, Jin Young didn't show that he was in pain and focused entirely on the recording. He collapsed right after he completed the shoot and was rushed to the hospital, where he was diagnosed with enteritis (intestinal inflammation)." The music video stars Baro as the main character, who acts as a stereotypical, B-blooded guy; it tells the story of a man who asks for forgiveness from his upset girlfriend. Source: OSEN via Nate