Welcome to HCM.
If you suspect that the lesion you have on your chest could be cancer then you should consult a dermatologist
and let him examine the lesion and if necessary do the required tests to confirm or exclude malignancy.
Without seeing the lesion or doing the necessary tests, it is not possible to give an opinion.
Since you have the suspicion, the best would be to consult the doctor and clear your doubt.
Wish you all the best.