I just use my regular under-eye concealer for my under-eye veins. I am super pale, so I have some veins that show there and then around my mouth. I just dot on some concealer, and then pat it in with my ring finger, and set it with loose powder.
Most people notice little things about themselves that no one else notices - I'd suggest taking a couple pictures of yourself and see if they are visible there. If not, I'd say you don't actually have to worry about them being visible to other people. You could even do a before and after with concealer.
Just remember, the more you point them out to other people, the more people will start to notice them!