I have developed a cold sore on my inner lower lip (whitish )and a single pimple(on my penis base close to my scrotum) that has now become kind of an ulcer because the upper skin(where the pimple originally was) has peeled off. This is 4days after exposure (condom slipped during sex we both tested negative for hiv). Could this be an std? Syphilis herpes maybe? I have No other symptoms .