I've been a barefoot walker for a lot longer than I've been a barefoot runner, and every spring I have to build the heel skin back up. If you do it gradually, you won't get blisters. If you do it too fast, you'll get blisters, mild and severe.
I tend to heel-strike when walking, but if the surface is rough or hot, or if I'm tired, I'll kind of reach out and land with my forefoot first.