My Sister Is In Hospital With Diagnosed Of Cellulitis. She

My sister is in hospital with diagnosed of cellulitis. She has end stage COPD, has been on steroids and I believe has had this problem with her leg for 5 weeks in rehab following a hospital stay. She has also the issue of CLL (chronic lymphosidic leukemia)
She was taken back to hosp again today and I am in PA, she 150 mi away in Silver Spring MD.
They are doing a scan to see if surgery is needed. Makes me very nervous....so I am looking for information about cellulitis