Hello, Welcome to healthcare magic, What you are having is a condition called Acute Telogen Effluvium. When you had Dengue a lot of hair went into resting phase or telogen phase and they fall off after 2 to 3 months. You should take Vitamin supplements containing biotin, calcium pantothenate and minerals for a duration of atleast 3 months (eg: Follihair/Keraglo eva/ Proanagen), not becosule. Biotin rich foods are carrots, almonds, walnut, cucumber, cauliflower, milk and eggs. Eggs also have protein and amino acids required for hair growth. Please do not take stress. The more stress you take, more the hair fall.Telogen effluvium is hair shedding. Your hair follicles are intact and they will produce new hair. If possible just check your Hemoglobin and Thyroid function test and treat if they are abnormal. Hope this helped, Take care