HERPOTHERM® formerly known as Hot Kiss®. Treat that tingle! Stop that Cold Sore appearing!.. Herpotherm® is a revolutionary new way to combat cold sores. When used at the tingle stage an outbreak can actually be prevented. Even if your cold sore has already started to come out this heat stick can significantly reduce the size and extent of the sore. It can even shorten the length of time your cold sore lasts and the amount of time it takes to heal. There are no chemicals involved or creams/ointments to apply. This is a medical device developed, made and tested in Germany which has been designed to prevent the development and advancement of the herpes simplex infection. How the Herpotherm® works: The device works by means of a concentrated heat source of between 50-51°c. This prevents the herpes simplex virus from reproducing.