Not to worry.... it's very unlikely that the backstay may have permanently deformed the mast.
These B&R rigs get a good deal of their stiffness from the swept spreaders,"X" shrouds and a fair bit of prebend. As a result any tensioning of the backstays of these masthead versions pretty much all goes into headstay tension.
Your pictures are not at the optimum angles, but it does look like the bend is not uniform over the section, and could use some tuning.
1984 Fast/Nicholson 345 "FastForward"
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)