Hello, Welcome to HCM, The pain caused by the herpes zoster viral infection will be very severe and untolerable. The virus will remains dormant for many years following the infection and whenever the immunity comes down it will activate and produces the symptoms like blisters, rashes and excruciating pain. The antiviral drug will not treat the condition but it will inhibits multiplication of the virus and prevents the complications it should be initiated as early as possible to prevent the complications. It is a self limiting disease it will come down by itself. I would advise you to follow 1.Antiviral drugs 2.Topical Calamine solution 3.Applying Neem leaves 4.Oral Antihistamines 5.Oral NSAIDs. These remedies will reduce the pain and also fasten the process of healing and prevents the complication. Thank you.