I believe, in the combat log, it handles resistance on the attacking side of the equation - so if you check the damage you take you will only ever see flat numbers, with no mention of resistance, but if you check the damage that the enemy dealt, on their attack roll, that should have the resistance calculated in on their side.
Bear in mind, that since they released Barbarian, and without seemingly any intention of fixing it, Larian have implemented Rage incorrectly, resulting in it ending a lot more often and more easily than it should - Rage continues, normally, as long as you either make an attack or take damage before the start of your next turn; this grnat the barbarian a certain amount of flexibility without worrying about losing their rage. As Larian have implemented it, however, if you don't make an attack on your turn, your rage Immediately ends when you click the end turn button, when it should not. This means that if you use your action to do something else, on the assumption that you'll most likely take damage from some source before the start of your next turn, or that you'll probably get an opportunity attack before then, you don't actually get that benefit and cannot make that tactical choice, since your rage will end immediately regardless, and you won't have resistance to the damage that you take, and which should have prolonged your rage.
This has been reported as a bug, but there has been no sign that they intend to fix it.
