Re: Herpes on the stomach???!
Well you can never rule anything out and I hate to be the bearer of bad news, but it sounds like you might have contracted herpes on your stomach. You can get herpes anywhere, but since you said it's right above your pubic line I would be suspicious. The best thing you can do is go have the lesions swabbed and cultured while they're there so the doctor can tell you for sure if you have H or not.
It also doesn't matter if you're sexually active, and how long it's been since you've been sexually active. The virus can remain dormant in your sytem for years. You stated you already suffer from cold sores. You could have engaged in oral sex with a mate or kissed him, then he performs oral sex on you, and bam, you've got it. Autoinnoculation is rare, but it does happen.
Best bet, get tested and know for sure so you can go forth with a treatment, depending on what it is.