Im so worried about this help please

Men's health
1

image

638210821225655327.jpg) this lump appeared on my penis shaft 4 days ago its firm, smooth, tender but no painful and it has a base, mobile with the skin but not attached to underlying structures what is it and what should i do?
2

Looks like it might be full of fluid or some substance. Please see a doctor as soon as possible. Don’t risk it getting worse. It could pop or get infected (if it isn’t already).