Dreaming of a blister is a warning against an evil acts, scams, and frauds. It warns against fines and even jail time.
Dream dictionary: Blister dream meanings
Lucky enterprise.
(See Spanish fly)
(Blister beetle) A Spanish fly is a bad omen if seen in a dream by someone who indulged in abominable and loathsome actions. As for the majority of people, seeing a Spanish fly in a dream is more ominous. However, if a druggist, or a pharmacist sees a Spanish fly or a blister beetle in his dream, then they connote medicinal benefits.