I am finishing a round of treatment of flourouracil for actin keratosis, pre cancer spots, on my arms. Coming home from school in the spring I would go outside and help Dad do what ever. My arms got sunburned to the point I had blisters from sunburns. I had reddish blonde hair and fair skin. Thankfully never went without  a shirt because of that. I have had this for 15 years or so. Skin Doctor said I should not develop melanoma as long as I treat the actin keratosis. I am now 73.