Dreaming of a blister means over working and over stressing a particular aspect of life leading to the destruction of the very thing you want to strengthen. This is an indication that you need balance in your waking hours, otherwise situations will not get better just because you are trying to will a better outcome.
A blister in a dream is also an indication of a troubled area in your life that is festering into the open that cannot be ignored. A work project, that you are involved in, may be rolling over into a bad outcome. A neglected relationship may be coming to an end. Dreaming of a blister is nothing to joke about.