My mom, age 78, with high blood pressure, edema , developed DVT and was hospitalized for 5 days - heparanized, while also watching renal function - renal function improved back to her normal within the 5 days - she was released from hospital on coumadin. Now has large blister on leg, filled with fluid - due to edema and possibly cellulitis (she was also diagnosed with that while hospitalized, and is on antibiotics for that). Any suggestions on caring for the blister?