Thanks you for asking this question. I have undergone through your question. I understand your concern. Sweating in summer is normal but sometimes excessive sweating is a sign of disease. First of all, visit any hospital and get your blood pressure measured, and give a sample of blood for fasting & after meal test of blood sugar. Deficiency of vitamin D also causes excessive forehead sweating, so get done your blood vitamin D level. In the mean time you can use dusting powder. I hope this information will help you I wish you a good health