Thank you for your query. Dengue is a viral disease that spreads through mosquito bites. Any Fever can be associated with muscles pain and headache and is non specific to diagnosis of Dengue Most cases of dengue resolve on its own. In certain people, there may be complications such as bleeding, liver, kidney failure. They will need supportive treatment at the earliest to prevent worsening of the condition. ( most commonly there is an increased bleeding tendency that can be corrected by administering blood products if the values are too low) Dengue is confirmed by a high clinical suspicion and the detection of antibodies to the dengue virus ( Dengue IgM) Any fever that lasts for more than 3 days without showing signs of resolution and worsening of symptoms and overall condition shoud be evaluated throughly. See your doctor if his symptoms persist. Signs of recovery would be reducing temperatures, improvement in overall health. You mentioned spots on his legs. monitor them closely to see if they spread or increase in number. Let your doctor know. If he becomes drowsy, bruises easily, has bleeding anywhere includin gum bleeding while brushing teeth, small cuts that dont stop bleeding, visit the ER and have his blood work done to look for clotting factor deficiencies. Hope this helps. Wish you both good health. Please get back to us if you have further queries