What Causes Chest Patches With Bubble Filled Pus And Discoloration?

Hello. I have 3 small patches on my chest and shoulder of what looks like impetigo - they are patches of bubbles filled with a honey coloured fluid. I have had them for about 3 days now and some of the bubbles look to be turning dark or black (especially some that have burst). the thing that puzzles me is that impetigo is only supposed to contractable by infants of under 2 years? so could it be something else?