Hands can have herpes - it's called herpetic whitlow. However, they are only infectious when a sore is present, and those sores are noticeable and painful. I doubt anyone would be giving handjobs while having that kind of sore present on their hand. Most people who get whitlow are oral health professionals who have their fingers in people's mouths, and it's usually hsv1. If you google herpetic whitlow and look at images, you'll see that even the more mild images look pretty bad. You'd notice it.
Syphilis can cause a rash on the hands in the secondary stage. That's also noticeable.
A cut-like mark can be caused by lots of things - irritation, friction, herpes, - the list is long and varied.
You should get to a doctor today and have them look at it. Ask them to do a type specific PCR swab on it to test for herpes. If they think it's friction, irritation, a fungal infection, or something else, that's entirely possible, and there's no reason to doubt that diagnosis.
Let us know what happens.