Sunburn & Skin Cancer

I just got mild sunburn on my nose. I have had it there before. Should I be worried about cancer. As a child I was burnt (as most kids were of my age, now 37) on vacations too. I always try to cover up, but always get caught out. I was surfing yesterday and I guess my sunscreen washed off. I'm just overly worried as I have moles and try and take great care of my skin with regard to the sun. I go regulary to a dermatoligist and have had moles taken off, but none have been cancer so far.