Did you see bristles sticking out of those exact spots? If you were actually stung, it would be no question....they do not leave one or two bristles but rather a whole BUNCH that are impossible to miss. I brushed up against one a few weeks ago, and my finger looked like a toothbrush.
Those bumps are mentioned frequently on the net though...and they are most often caused by reactions to "stuff" in the water or touching corals. Regardless, gloves would keep any such thing from occurring again and protect your tank from contaminants as well.