What Causes Itchy Red Blisters On Penis After Intercourse?

hi. i am circumsised the day after sex i woke with an itch on the end of my penis, also a small red spot like a blood blister just in the opening, the surround to the opening seemed puffy. it is 30 years since any sexual contact wit anyone exept my wife. any clues i am 59 . 5ft 11 and 13stone. i have passed a couple of stones in the past thanks