Hello and welcome to HCM, Brown and yellow colored spots on penis are unlikely to be due to any sexually transmitted disease like herpes simplex infection. The brown colored lesion with a discoloration in the middle could be some pigmentary disorder. Pigmentary disorders are those which are caused by proliferation of melanocytes or pigment containing cells in the skin. Pigmentary lesions vary from simple moles to more serious ones like melanoma. Thus, I suggest you to consult a dermatologist and venerologist for clinical assessment and relevant investigations to determine the cause of brown colored lesion. Further management will depend on the cause of the lesion. Simple moles do not require any treatment. Follow up of these lesions is sufficient. Dysplastic moles or melanoma require aggressive treatment. Thanks and take care Dr Shailja Puri