You are so right to be concerned that your grandmother get care with cellulitis...and quickly. Not only does this disease progress quickly, but she must be in extreme pain all over, not just the inflamed area. I've had cellulitis 4 times on my abdomen and then got panniculitis. I am now trying to recover from a panniculectomy. I had no choice but surgery. Hopefully this won't happen over and over with your grandmother.