Skin Cancer Questions

Questions about skin cancer

Of course everyone says wear sunscreen, but I read an article like a year ago that sunscreen could actually increase your risk of getting skin cancer because it prevents some important things from getting absorbed into your skin or whatever it is. Has anyone else heard about this?

I have a mole on my stomach which has changed in appearance, it used to be raised and is now flat, it also has uneven edges and has a red/pink ring around it. It has been like this for a while as I kept forgetting about it. It doesnt itch and is not sore or irritating. I have a appointment with the doctor on Friday but after looking into it on the internet am getting really worried, are there any other signs of skin cancer I should be looking out for?