Last Thursday I went to the zoo and got bitten by some sort of insect. Within a few minutes my forearm swelled up a couple of inches on either side of the bite. Aside from the slight swelling of my forearm and fingers and a hoarse voice it didn't get any worse so I didn't think much of it. As of today the swelling has gone down for the most part but the redness is spreading up my arm a bit. It is mildly itchy but nothing unbearable...
Do I need to call my doctor because the redness is moving up my arm?? I have no idea what bit me so I have no clue what a doctor could do for me but I'm just not sure.

The majority of the swelling was between the dotted lines and the bite was right about in the middle of that area. The funny blob that I outlined is where the redness is now.

What would you do??