You might actually just ask the priest why he did that. Perhaps he slipped up; at some point during the Mass, of course, he would have said the words “Peace of Christ.” There is no need to presume ill will on the part of the priest. Furthermore, if this were an abuse and not a simple slip of the tongue (priests are human, and flub words from time to time), I’m not sure this rises to the level of the kind of thing that needs to be immediately addressed to the Bishop. Speak to the priest if you’re concerned, but I don’t think this is something that you’d necessarily write the Bishop about. In the grand scheme of things, liturgically speaking, were this an intentional action of the priest, it’s still a relatively minor quirk, and not a huge abuse.
-ACEGC