Suggest Treatment For Redness And Swelling In Calf

I am a 61 year old male. I am experiencing a lot of pain in my upper right calf. The area is about 4 inches long and is red and slightly swollen and warm and is on the inner part of the calf. It is tender to the touch and at times very uncomfortable to walk. At first I thought I may have gotten an insect bite and this was a reaction, but I can not detect any point where there may have been a bite. this pain started 2 days ago and it is still swollen and red and the pain level is the same as when it first started and has not subsided.
I do not have any nausea or fever.