Onset 2.5 mos ago. Red smooth marks on penis. Itchy, red and sore now on scrotum, legs and butt. Scrotum is always red. No stds. Treated 1x for yeast?

Fungal infection. A yeast or fungal infection is possible. An antifungal cream may help. Keeping the area dry and clean will help. Athletes get fungal infections on their feet and call it athlete's foot. Some people call fungal infections in the groin "crotch rot." sometimes steroids have to be used with anti-fungals to reduce the inflammation.