I have a lesion on my left arm. It is reddish in color and when pressed the red goes away and theres like a freckle underneath in almost a star shape and another smaller freckle right next to it. It is smaller than a pencil eraser, its about 4 mm long and maybe 5 mm tall. It is slightly raised. It doesn't feel hard or irritated. I first noticed it 4 months ago and had my doctor look at it at my physical. I was told to go see a dermatologist if it got bigger or changed at all. In that time It hasn't changed at all, it stays the same size and looks like it did when I found it. Also looking at a pic of myself from last September shows it on my arm, and at that time it looks to be the same size. (I just never noticed it, its on the backside of my arm)

Could it be cancerous? My doctor gave it a good look over and didn't seem very concerned.....