I think you don't have herpes, which produces clusters of blisters, not a single bump. I think the various symptoms you have indicate not herpes but anxiety. To get a proper read on the bump, the brown spots, or any other penile anatomical concerns, I recommend that you leave the penis alone so as not to confuse the issue, and to see a doctor for proper diagnosis and counseling.
But it does sound as though you're OK.
Best.
Dr. Rockoff