Hello. Three days ago, something (I m not sure exactly what it was because it was swatted away before I got a good look at it) stung me on my lower calf. I went home and examined it, it was red with some swelling but I couldn t see a stinger. I put some baking soda with water over it and the swelling and sting went away. In the last couple of days it would itch every now and then and only looked slightly red. Tonight after getting off work, I looked at it and saw that it a purple patch had broken out around the area of the sting. I do not have a fever or feel sick, but I m not sure why the skin would be turning this color.