Following the Klingon Empire's withdraw from Cardassian space, Japar's Bird-of-Prey returned to Deep Space 9 where it underwent repairs. While at the station, Japar was taken to the infirmary with plasma burns. According to "Julian Bashir", his wounds looked worse that they were.
Miles O'Brien was trying to track down Japar because he was unable to "make head nor tail" of the power relay systems on Japar's Bird-of-Prey, but he had just missed the lieutenant by the time he arrived at the infirmary. (DS9: "By Inferno's Light")