Baseball..if the starting pitcher leaves in the 8th losing 2-0, then his relief gives up 2 more to make it?

4-0, but his team rallies for 3, but fall short in the 9th...who gets the L? Also...if a reliever comes in a 'non-save' situation, but then allows enough runners to reach to make it a 'save' situation, then 'saves' it, does he get the save?