Looking for anyone who has med background to explain what this red bump on my penis could be

Lack of sex bump.

It’s not about just showering. You need to clean that thing more than just faping in the shower. I would recommend rubbing it down with soap in the shower then rinsing. Try to do this after faping

What would explain the hard bb sized lump under the skin though? The cause of that?

Mediterranean here, not sure what it is.

Have you been fapping in any odd ways recently?

probably a pimple or a cyst. although if you're not an american and you can visit a doctor without collecting debt I'd suggest to hit your GP up.

You shaved the base of your dick and got an ingrown hair

funny

Aids

I shaved 3 days after it showed up