I wanted to know if you snap a +4 or +2 does it reset the amount the person picks up?
Chaning/Snapping/Stacking draw cards does not reset the penalty amount. E.G Player 1 plays draw 2, player 2 plays another draw 2, player 3, having no draw 2 cards, must draw 4 cards.
From wikipedia as a part of the house rules:
Progressive Uno: If a draw card is played, and the following player has the same card, they can play that card and "stack" the penalty, which adds to the current penalty and passes it to the following player.