First, herpes doesn't cause pimples or lumps. It causes blisters.
Herpes blisters last a couple of weeks at the most, and as you said, they scab and then heal.
Not seeing a doctor because you are too embarrassed to deal with something you have is a dangerous thought. The longer you wait to treat something, the worse it could be. There's no shame to anything on your body, and people have sex. It's a normal thing we do. Your doctor has seen far, far worse, I promise. I used to work at an STD clinic, and I can guarantee you that whatever you show your doctor, they have seen and heard worse.
So what is causing this? It could be just pimples. It could be a staph infection. It could be a mild case of folliculitis (infected hair follicles). The only way to know is to get checked. You should get them checked, though, since you've had them for so long and they aren't going away.
It doesn't sound like anything serious, but you should get it checked. Let us know what happens.