Yes, since Blood Rage (Utito Tempo) is a Stance now, you can use Berserker Potion to get more buffs on your skills.
Before, it wasn't possible because Utito was a temporary buff and Berserker Potion or even Foods that granted temporary skills would replace the buff that was applied first, so now you can use Berserker Potion, Delicatessen Salad (House NPC Food) or Veggie Casserole (Hot Cuisine Food that gives +10 skill) to get an additional buff with your Blood Rage Stance.