Suggest Treatment For Rash,sore Throat And Abdominal Pain In A Child

My 4 year old daughter developed a faint rash on face and neck which resolved after 2 days. The day the rash developed she had what looked like a mosquito bite (areas was itchy & pustule-like) on her arm. Day 2 she was feeling well. On the third day she developed sore throat, headache, fever, 3 episodes of diarrhea, and vomiting. Went to MD & strep test was neg. Day 4 she was extremely fatigued and no appetite. She would vomit in the morning only day 4, 5, & 6. She continues to complain of sore throat and abd pain. She is extremely weak. Also complaining of leg pain, doesn t want to walk. I have been able to keep her hydrated. Live in Northeast & frequently outside. Live in an area with a lot of ticks. Have not noticed any ticks on her.