Hello I appreciate your concern. Rashes with sore throat and weakness might be related to viral or bacterial infection or inflammation of the throat. I would advise you for a battery of investigation like CBC, ESR, CRP, liver function test, X ray chest if she has coughing and breathing difficulty. She may require a course of antibiotics or antiviral under medical supervision after establishing a diagnosis. In my opinion you should take her to the paediatrician for physical examination and prescription of medicines. Meanwhile ask her to do gargling with warm saline water Apply lactocalamine lotion on the rashes. Hope this answers your question please feel free to ask for follow up question I will gladly answer you. Best wishes