Sebaceous Prominence - Some larger than others?

I have a Sebaceous Prominence on my testicles, however I have one or two that is larger than the rest. The others are just small, you can barely feel them, while the one in particular is bumpy and looks like a pimple. I've had it for maybe a little under a year now, and I notice it off and on but it's never caused me problems - it never hurt, itched, anything.

I know Sebaceous Prominence is normal, but how about the pimple like ones? Are they just larger, infected, or what? Should I be worried?