What Causes Itchiness,swelling And Redness In Penis?

Dear doctor , since a week .initially it was itchy n swollen,after two days. there are well define 3 crater are form on my inner flesh of my penis shaft,raised borders little wetty,slight yellowish. But no pain or itchy..surrounding is little red n swollen but no pain any where.. no fever too.. m normal. What could be.?. I need medicine. M confused n scared too ..is it chancroid? Or primary syphillis? or hsv2? or something else. ?M male 39 yes. Never had such decease earlier. Pl let me know best treatment medicine too .thanks