The fact that it mentions two very specific locations, the right hand or forehead, would suggest to me it's literal, especially since not everyone has a right hand, but everyone alive has a forehead. What if by taking the mark they become so
J.
that they become incapable of repenting? Romans 1:28 would seem to imply that "and because they did not think it worthwhile to acknowledge God, God delivered them over to a corrupt mind so that they do what is not right." At a certain point, blasphemy's threshold is crossed, and there's no going back.