My vein on the outside of my left index finger hurt when gently touched. No redness, but my vein is really visible. Mild swelling....btwn my thumb too?

Phlebitis. supeficial one. Usually resolves with local treatment of the inflammation with warm compresses and anti-inflammatory medications such as advil or aleve (naproxen). Having said that i would like also to tell you that sometimes superficial phlebitis can be associated with deep vein thrombophlebitis which is dangerous. So, see your doctor for a medical evaluation.