Hi, I Had A Traumatic Accident Where A Red Light

Hi, I had a traumatic accident where a red light runner hit us...no broken bones, but the next day my face, lips and eyes swelled up suddenly...Afraid my throat could close, I went to ER...A few weeks earlier, I'd seen my doctor for waking up with welts/bumps on my legs which went away in a couple hours, then reappeared the next morning...Now insurance won't pay for that ER cost, citing a "pre-existing condition"...but I'm sure it was a response to the trauma of the accident...So my question is, can these symptoms be caused by a traumatic accident? There were no other unusual factors (foods, medicines, etc.) Thank you!