What is this?

My 15 year old daughter has been dealing with some health problems lately, we were in the emergency room last month because she’s been having bad shortness of breath. They referred us to a cardiologist & pulmonologist. Her appointments aren’t for another 2 weeks.

About a week ago she started developing these red lumps on her leg that turned into bruises, she’s had a constant low grade fever and there’s little bumps under her skin. She has about 5 pea sized bumps under the yellow bruises & the big red spot is a huge lump under her skin that keeps growing. She’s been complaining about her breathing & pain from the bump. I’m not sure what to do? The emergency room didn’t do much last time we went. I’ve been giving her advil for the pain because she’s been having a hard time sleeping.

Any idea what this is? Should i take her back to the emergency room?