I am sorry to say that infection of hand needs a good antibiotic like Clindamycin
.Corticosteroid like Decadran is not necessary.Anti inflammatory drug has to be added.As her serum creatinine
is high anti inflammatory drug should not be given now.
You did not mention the serum creatinine values.If it is very high,She has to go for Dialysis
Swelling in body and increased weight can be due to Decadran.
The infection might have spread to the kidney
and led to high serum creatinine levels.
Please consult a Surgeon for further followup
Wish her speedy recovery