Its too early to say with any degree of certainty that the tit for tat game is over, but there is reason to think it is. Iran had to do something or look weak and fearful, especially since they took their rhetoric campaign to a new level. So they choose Ain Al Asad and Erbil at their targets.
What does this attack tell us, if anything? For starters look at the time of attack, the early morning hours when the least number of people would be roaming around the two bases. So we have no American military deaths. Military bases have the best air raid warning systems and Iran knows that, but they still chose to hit these two military targets located in sparsely populated areas. The rhetoric in Iran has also dropped off significantly.
I would suspect the leadership in Iran was looking for a way to save face, yet not prompt a retaliatory strike that they could not handle. Given their faltering economy they dared not provoke the US to the point of a serious response. They oil fields are prime targets and we have the ability to inflict an economic catastrophe, they sure didn’t want to risk that. So, it appears Iran did the worst they could, which really wasn’t much. It’s looking like Trump might have won this round.