Hello and welcome to justanswer.com. Follow up questions are welcome. Well red blotchy rash in context of fever can be sign of a vasculitis, or inflammation of blood vessels. Headaches can occur in addition to joint pain and abdominal pain. Systems often follow respiratory infections, sore throat, or other infection. The rashes in Henoch Schonlein Purpura (a form of vasculitis that usually happens in kids but can happen in all ages), for example, tend to be found in gravity dependent areas such as the legs ("lower part of right leg"). Symptoms can last to about a month and complications of the kidneys can result becuase they are quite vascular. The test for these types of vasculitis are urinalysis to test for kidney complications and skin biopsy of the rash.
I hope this helps. I am pleased to assist you. Thank you for this great question.
If the bite was at same the location of the rash this is likely. However, insect bites can also trigger and inflammatory response that can lead to vasculitis (less likely, but possible). That in addition to the fever, would imply a serious bite capable of causing such vasculitis. Whatever the cause of vasculitis, still you need a urine test, biopsy, and a prescription for medication (including steriods).
I do hope this provides a little more clarity.