I’m fairly confident it is just pimple. He has a birthmark on the center of his chest
and a tattoo on his shoulder but other than that I don’t know of any other marks on him (or I just can’t think of any right now). Some people are prone to get pimples in the same location and stress, sweat and excess make-up can speed up pimple production.
Thanks for the question, feel free to come here with more questions or submissions.