my SO might have herpes, what do I do?

We've been dating for a few months now, and then one night recently while things were heating up and I unzipped his pants, I noticed red patches and bumps on his member. I mentioned it to him, and he insisted he doesn't have anything, and that he hadn't had sex with anyone for more than a year before me, but I know he's "hooked up" with other girls without sleeping with them and I don't know what that entails. We've always used condoms, but I've given him blowjobs before, and now I don't know what to do. Can I continue to have a sexual relationship with him if I'm unsure of what's happening down there? Should I get tested? How can I ask him to without hurting his feelings? I just genuinely don't know what to do now, any input will help.

edit: Thank you all for the great advice! I'll definitely be using your suggestions.