The ERAPROTECT protection pen against fever blisters is a medical device to protect against cold sores (herpes labialis), which are triggered by solar radiation. ERAPROTECT should be used in strong sunlight. The effect is based on a UVA and UVB filter. The sun protection factor of 30 protects the sensitive skin of the lips against UV radiation. In this way, the activation of the virus and thus the occurrence of fever blisters can be prevented.