You guys, I almost in tears. I know it's ridiculous to be so upset over a plant My Christmas/Easter cactus (I've never figured that part out, I just call her My Baby) I've had her for 14 years and have never had any problems. A few weeks ago I noticed colored spots on some of the leaves, some leaves are wrinkled and very thin. I don't see any bugs. It only seems to have affected one section of the plant.
My plants always spend the summer on the porch where we live in Washington state. They love it and grow like crazy. I brought her in in September.
The only two things that have changed is she flowered like crazy in October, more flowers than I've ever seen. She is budding again now, which is odd.
The other change was she was outside this summer for the 3 days and it got hot, 112 degrees where normally our average temp was 85 degrees. I had her in the shade, she did just fine, no sunburn, no wrinkled leaves. Two months later is when she had her gorgeous flowers.
So there you have it, the life story of my baby. Any ideas on what's wrong?

To me the damage looks mechanical. What is your watering schedule? The soil mix?

Just an equal mix of regular potting soil and succulent soil. I think the water spots you might see on the plant , 4th photo down, are over-spray from when it was outside this summer and I watered nearby plants. I should probably give it a good wipe down. For watering I use a plant hydromoter and I water when it reads dry. I've been doing everything the same.. watering, soil, winter and summer placement etc.

The area where the plant is located seems too dark.

When was the last time you transplanted it?
If your dirt mix is old you might have root rot.
The wrinkled leaves look like drying up.