Pep Guardiola had a cut on his nose and scratches on his head after Manchester City's 3-3 draw with Feyenoord in the Champions League on Tuesday, 26 November.
The Catalan arrived to speak to the media with visible marks on his head.
He said he caused the nose scratch himself with a long fingernail.
The City boss described the result as "difficult to swallow" and admitted he understood the boos that greeted the final whistle after his side threw away a 3-0 lead in the last 15 minutes.
