Have it evaluated by a Dermatologist. Very easy to misread cancer warning signs. I had what I thought was a round red pimple that would not go away and it turned out to be Squamous Cell skin cancer that had to be surgically removed.
There are some things you should look for in determining whether or not it's skin cancer -
A = Asymmetry
One half is unlike the other half.
B = Border
An irregular, scalloped or poorly defined border.
C = Color
Is varied from one area to another; has shades of tan, brown or black, or is sometimes white, red, or blue.
D = Diameter
Melanomas are usually greater than 6mm (the size of a pencil eraser) when diagnosed, but they can be smaller.
E = Evolving
A mole or skin lesion that looks different from the rest or is changing in size, shape or color.
However, just because it may not be skin cancer (and I have no way of knowing that or not), it doesn't mean it isn't something that needs to be treated. You should definitely have a doctor take a look to be on the safe side.
Let us know what happens.