What Causes Itchiness And Blisters On Skin After Intercourse?

AM A MALE STRAIGHT AFTER I HAVE SEX AND I CUM I HAVE A SKIN REACTION WHICH I GET ITCHY ALL OVER THE BODY REDNESS TO THE SKIN AND MY SKIN BUBBLES JUST LIKE A MOSQUITO BITE THIS HAPPENS TO THE BACK , ARMS, CHEST ALL OVER BUT GOES AWAY AFTER AND HOUR OR SO. HAPPENS ALL THE TIME AFTER SEX. DONT NO WHAT IT IS?