Mom is 78 and had larynx cancer a year ago. went thru chemo and radiation. smoking and drinking again. unidentified "rash" and melanoma? see pics

Not enough history: The fact that mother is doing smoking is not good but not uncommon. The area of the rash is not clear as the pictures are not available. The rash if around the neck or in the radiation area may well be related to the radiation burns. There is not enough information to say about melanoma is unusual in this setting. See the oncologist.