I have a painless white bubble on my upper lip tubercle. it seems to sometimes enlarge and shrink, not sure what causes it. does not go away and it blends with my skin. there is no cluster of bumps or pain. could this be herpes or a fordyce spot?

Herpes is not possible, based on this description. No herpes lesion ever lasts more than a week or two. Maybe Fordyce spot, small cyst, fibroma, or something else. You'll need to see someone in person, or consider HealthTap's concierge service, in which case a dermatologist may be able to examine a posted photo. In the meantime, for sure don't worry about herpes.