Raised Brown Skin Growths on Shaft of Penis

My boyfriend is 60 years old.  He's a business executive and frequently travels to Europe and South America.  He's healthy and take care of himself.  On several occassions, during sexual arousal, I've noticed several raised brown spots on the shaft of his penis.  Anywhere's between 1 to 3 at a time.  Usually in the same area, the upper to mid shaft of the penis.  One was raised, round, brown and the size of a pea.  The other was brown and looked like a skin tag.  He also gets a few zits on the penis.  They come and go.  Also, he has skin cancer on his face, a few basal cells which he is under medical attention for. I'm I uncomfortable discussion this with him.  Is this anything for me to be concerned with.