Well obviously, the time for you to notice and correct the error was before you flew to Majorca. But that window is closed.

If it is noticed and you are denied boarding on the existing ticket, you should be able to change the ticket for a fee. I see no reason to do so until and if that happens. Just act surprised as suggested and go from there to get it changed to match your ID.

Often, people see what they expect to see. I suspect that is what happened on your outbound flight. The Ryanair agent who checked your ticket against your ID, saw what s/he expected to see, the same name. It may well happen again on the return.