You say it's elongated - how long is it?
It could be a sebaceous cyst or a Fordyce spot (which is just an oil gland).
It's not HPV/a genital wart. That wouldn't last 3 years with no change. It's not molluscum - same thing, it wouldn't last that long with no change.
A syphilis sore is red, round and painless and only lasts a few weeks, usually.
You really should see a doctor. Your doctor views your penis as any other body part and has seen everything. I know it's embarrassing for you, but your genital health is just as important as any other part of your body.
Go get it checked out, and put your mind at ease.
This could also be lichen sclerosus or very many other things. Does it itch, hurt, bleed? Urologist would be my first choice since hes/ her job is to look at many penises dayly and knows the best all the diseases of a penis. If needed, they will refer you to other specialists. Good luck and get well soon!