I think this idea is very sound. Anything to save one's skin works with me. You might be able to pitch this to a Chinese manufacturer and see how cheap they could produce one. Then shoot the concept to the ADA (American Dermatological Association) to see if you could get any traction there. If you managed to penetrate this market place then it could be assume that you would gain one sale for each person diagnosised with a melanoma. Since it could be labeled as "preventive medicine" insurance companies might agree to pay for it if it is cheaper than treating skin cancer. From there you might gain acceptance in the general market place for concerned Mom's which would bleed over to the general population. Good thinking.

Years ago I seen a wristwatch with such a sensor.

This product could also be marketed to sun-bathers who want to get a tan without getting burned. That's a big market, this idea could be worth considerable money! Good luck!

Excellent idea.

A lot of good products and ideas appear and fade away because of their bad timing. I think you have the right idea at the right time. Both in terms of awareness and the technology to develop it. I have a good feeling of its being a great success.

Go ahead, make it work. Good luck.