I re-watched the hit multiple times and it looks far cleaner than some are making it out to be. It is difficult to assess without seeing another angle but I did review an HD version of the hit and slowed it down frame by frame. From what I saw the principle point of contact was Peric's left shoulder and not his head. Peric even looked like he attempted to dodge the hit by moving to his right, that he saw the hit coming at the last second made an attempt to evade it but that the net limited his room to move. Boucher landed a clean hit to Peric's shoulder.
The issue will come down to what Boucher did with his stick. As Boucher looks to initiate the hit he swivels so that his right shoulder will hit Peric's left shoulder. By doing this Boucher's stick goes from outside Peric's left shoulder to across his body. After Boucher lands his hit to Peric's shoulder, and as Peric is simultaneously falling into the net from the hit and attempting to evade the hit, Boucher's stick ends up clipping Peric's helmet.
I'm pretty sure Peric played the rest of the game so he didn't sustain any injuries and it also makes it far more doubtful that the principle point of contact was the head. Actually the fact that he played the rest of the game suggests that what I stated above is likely a more accurate representation of what actually happened.
Interestingly, Boucher swiveling to his right to make his right shoulder the principle point of contact could actually be argued to be far safer than looking to initiate contact with his left shoulder. Once Peric recognized the hit was coming he looked to brace himself for the hit and shifted towards his right in an attempt to dodge it. If Boucher would have lead with his left shoulder then that might have increased the chances of the principle point of contact being Peric's head.
This seems consistent with all players in such a situation. A puck carrier coming from behind the net and looking to accelerate around it is likely to have their head shifted towards the net. Therefore if a player is looking to hit them, using the shoulder closest to the net and the player is more likely to result in contact to the head. Swiveling to use the opposite shoulder to initiate contact is a safer option and gives the puck carrier more time to brace for contact. But as we see in this situation a potential issue is stick placement.