Got a triangular brown spot on my penis, should I be concerned?

Probably not, but... What and how you reported seem not clinically serious, but it is hard to tell for sure without a analysis of detailed history stressing sequence of events + findings of inspection/palpation at least. To ascertain what it may be can be done by following instructions in https://ebettercare.com/feel-become-sick/, although clinically it may be an ectopic sebaceous glands. Best wish to health...