Getting lotion inside your penis could cause a feeling of warmth. Constantly worrying about your penis could cause a feeling of warmth.
If you have this much concern about a hand job, maybe you should rethink how you chose your sexual partners. Your concern/caution is better placed on the front-end of that decision.
A feeling of "warmth" inside your penis is not a symptom of herpes or any other STD for that matter. Even if she had an STD, you are at no significant risk.
Best,
Em