What Causes Lower Abdominal Discomfort With Red, Itchy Rashes On Upper Arm?

Hello my fourteen year old daughter is complaining of discomfort in her lower stomach. She is sick at the thought of eating. She has eaten today but not much. She is very pale but has no temperature. She describes the pain as if her cycle is starting but has only finished her cycle less than two weeks ago. She also had a rash that is on her upper arm, it s about four inches and was very red and raw but is pale and pale and very itchy. She also had a few patches of this on her other arm and upper back. THANK YOU!