Jeff here . . .
I don't know why I am going through this. That's something I'll probably never know. But I do know that I want to make sure no one else has to go through anything like this if I can help it.
So, if you are fair skinned or of northern European heritage (e.g. Irish, English, German, Polish, etc), have had at least one major sunburn in your life, or have lots of moles (dysplastic nevii) on your body, YOU NEED TO CALL A DERMATOLOGIST. Dermatologists are nice people. Moreover, because dermatology residencies are among the most competitive for medical students, dermatologists are also really smart people. A dermatologist can look at your skin to identify any potentially cancerous lesions.
When you call the dermatologist, ask for a skin checkup. Wear comfortable clothing to the appointment because you are probably going to have to shed most of it. The dermatologist will look at all your skin, including several places that you may not be able to see for yourself, like your back, your scalp, the bottom of your feet, even between your toes. If the dermatologist sees something suspicious, he may want to remove it immediately. LET HIM DO IT! Better to carry around a couple of stitches than a festering cancer.
If you live in Wauwatosa, I strongly recommend Dr. James Barnett. He is an excellent doctor. If you would like a reference to a dermatologist elsewhere, I will do my best to get you one.