How can you determine skin cancer on the collar bone?

Skin cancer : Skin cancer comes in many clinical forms. A questionable area such as the one you describe should be evaluated by a dermatologist for proper diagnosis and treatment.

Have new ones checkd: Although changes in our skin are normal as we age, if u notice new changes that r concerning have them looked at by your regular doctor. Most benign skin changes are easy to identify by looking at them. Skin cancer identification is defined by the a, b, c's. A- asymmetric shape. B- borders that are irregular, c-color (multiple colors are concerning) there are some more features but these r basics.

Skin biopsy: A biopsy of the suspicious lesion will give you your answer.