Abstract: A method and apparatus for treating lesions caused by viral infections including herpes simplex. The apparatus comprises a compact, easy-to-use instrument for controllably providing heat to the lesion site both from a primary built-in heat source and from a built-in light source which functions to complement the primary heat source and also to brightly illuminate the lesion site. The instrument also includes a novel bar graph, multicolor display which provides a visual indication of the instrument power setting as well as temperature conditions at the lesion site. Additionally, the instrument provides an audio signal to the user when the proper length of treatment time has elapsed.