Long clear blisters on forehead may be the appearance of sweat herpes, chickenpox, herpes simplex and so on, you can choose topical drugs and oral medication. 1. Sweat herpes: related to skin allergies, local infections or mental factors, resulting in patients with blistering dermatosis, causing clear blisters on the forehead. It can subside on its own in a few weeks, or apply tacrolimus ointment, pimecrolimus cream and other medications, which can make the skin recover gradually and also relieve skin discomfort. 2. Chickenpox: It is an acute infectious skin disease, caused by varicella zoster virus infection, which can lead to clear blisters on the forehead. Antiviral drugs such as acyclovir capsules and vasiclovir hydrochloride tablets can be taken to shorten the course of the disease. 3. Herpes simplex: Herpes simplex can be caused by herpes simplex virus infection, resulting in clear blisters on the forehead. Most of the blisters are limited and clustered, and you need to take drugs such as famciclovir dispersible tablets and acyclovir tablets, which can reduce the symptoms. Forehead long transparent blisters may also be eczema, contact dermatitis and other diseases caused by the patient can not choose the drug, need to go to the hospital in time, the above drugs should be used under the guidance of the doctor.