Hi, I Am Having Some Black Spots On Penis Glans

Hi,

I am having some black spots on penis glans just at the meeting point of head and glans. it pains while masturbating. also i have one white colored pimple between glans & frenulum. In Urination there was burning sensation and smell before but after taking some medication it went away. everytime i masturbate the pain comes back. Can you suggest me what these symptoms lead to.