What Causes Sudden Appearance Of Sore Swelling That Turns To Hard Mass?

Hi, I have been in hospital with a suspected infected sheith in my ring finger. After three days of I.V antibiotics I was sent home still with a swollen finger and 10 days of antibiotics. I have been waiting to have a scan but the swelling in my finger has possibly developed into a ganglion. All of this started 4 weeks ago. When I woke last Wednesday I discovered another sore swelling in my right palm. In the centre of the swelling is a small yellowish blister. I went straight to my doctor who has prescribed my with 7 days antibiotics but this swelling has also turned into a hard mass. I am due to have my scan on wednesday and go back to hand clinic on the following Tuesday. I am unaware of having injured both or even one of my hands and now i am suffering an achy stiffness in my finger. Just wondering if you can suggest anything?