I am 21 year old and becomes weak and thin after dengue fever at age 18. What should I do to come healthy.......

Med Eval. Most often dengue acute sx last 7 to10 days. Usually there is full recovery within a month. If you had dengue hemorrhagic fever or dengue shock syndrome recovery can be longer depending on complications. If it has been 3 years, recommend full medical evaluation with your physician to find out what the issue is.