I've been taking probiotics (100 billion CFU) for about 1.5 weeks ago, and got tiny raised acne (but have no heads) all over my face. Is this die off?

Unrelated. The skin changes you mention are a coincidence. They are not related to probiotic use.Whether or not they will persist or fade will depend on other factors.Discuss it with your doc who can actually see the skin and determine if treatment is needed.