Zovirax Cold Sore Cream At blister or tingle® Promotes healing Anti-viral treatment. - Prepare and Use: Apply the cream liberally to completely cover the whole affected area. Apply to the affected area five times a day at approximately 4 hourly intervals for four days. See enclosed Leaflet for further details. Consult your doctor or pharmacist before using this product if you know that your immune system is weakened. Always read the label.