My Fiance Has An Abrasion On The Shaft Of His

My fiance has an abrasion on the shaft of his penis and it seems to be seeping. He has been using Triple Antibiotic Ointment for 2 days. It is fine until we have sex and then it burns. Any suggestion as to what this is or what has caused it? He has read on other medical sites where it says it could be "caused by friction?" Could this be a possibility?