How do you know if you have skin cancer?

On my arm there is two spots that are a lighter color than the rest of my arm and it's sort of bumpy. not like really bumpy just like if I were to have permenant goose-bumps in those spots...can anyone help me?

[u]Here's what to look for:[/u]

A small, fleshy bump with a smooth, shiny, or pearly appearance.

A firm, scarlike lesion.

A bump that repeatedly bleeds and crusts over or hasn't healed for more than three weeks.

A red or tender flat spot that bleeds easily.

A transparent bump with tiny, visible blood vessels.

A smooth bump with a raised border and indented middle.

A red, irritated, crusty patch of skin that doesn't heal.

A shiny area of tight-looking skin, especially on the face, that looks like a scar and has poorly defined edges.

Any growth in a wart or mole.

Any change in the surface of a skin growth.

Any asymmetry or irregularity in the shape in a skin growth, e.g., if it's not an even shape on both sides, or the edges are jagged.

Any asymmetry or change in the color of skin growth, e.g. it's brown or black, or has dashes of these colors, or even red, blue, or white.

Any sore that does not heal.

You can google some tips on what to look for, but basically these only tell you what *might* be cancer. Next you have to go to a doctor to confirm.

The first answer is great, but you can also look for these signs -

Take note on your freckles and moles. Note their shape, size and coloring. Keep an eye on them regularly. If you notice them getting bigger, getting darker, and taking sort of an odd roundish shape, then you might want to go to a doctor just to be safe.

Also note where your freckles/moles are located. If you notice a spot that looks like a freckle/mole in a spot that you've never noticed one before, it might not be a bad idea to get it checked out.

Above all else, if you even THINK something might be wrong, go get checked out. It's much better to be safe than sorry!