What is Acyclovir used for? Uses of Acyclovir include reducing pain and boost the healing of sores or blisters in people who are suffering from different types of viruses including varicella (chickenpox), herpes zoster (shingles; a rash that can occur in people who already had chickenpox earlier), and first-time or repeat outbreaks of genital herpes (a herpes virus infection that causes sores...