recurring bugbite sized lump on genitals

im 24 years old and my issue started about 4 years ago when i noticed that there was a small lump underneath my scrotum. it was about the size and color of a mosquito bite but it did not itch and was not painful to the touch. it literally appeared over night and i was concerned about it until it disappeared over night about a week later. What seemed to be the exact same bump appeared again about 2 or 3 months later on the other side of my scrotum which got me worried that it could be some form of herpes but from everything ive read i showed no other symptoms of herpes and ive been tested for STDs in the past. over the past few years the bump has appeared somewhere on my scrotum every few months in a different spot. the most recent time this bump occured was just a few weeks ago except it was on the shaft of my penis which scared the hell out of me because it had always been on my scrotum... but just like all the other times it just disappeared over night without every causing me any pain or discomfort accept for it being an eyesore. what in the world is this meandering lump?! ALSO on the underside of my penis i DO have those little sweat gland bumps but i stopped worrying about those years ago when i realized that they are very normal. i figured id add that to this post in case they may have something to do with my wandering bump.