No, you can not change your stat point once they are distributed. You can use charms (permanent) or select equipment with bonuses to help with certain stats, though. Potions can help if you are having a problem with a certain area or opponent (ie use an intelligence potion if you are in an spot where archers keep hitting you with Stun Arrows).
Skills are arguably more important than stats, and equipment doesn't have any stat requirements, so if you want to switch your character build, you should be able to do so without too much trouble (post details for specific advice). Playing an archer on nightmare difficulty, I stopped distributing stat points after level 15, and made it to the end of the game without too much trouble (the places I did have trouble merely needed a couple extra potions or an adjustment to my strategy).
