I would transplant this guy into a larger pot, this must be 6" in diameter?, get a pot no larger than 8" in diameter, wider than tall. Clay is best and least expensive. These succulents tend to 'wrinkle' from lack of water. Lack of available water as well as having rotting roots unable to take up enough water for the plant's needs.
Use only potting soil, nothing else at all except this plant in that soil in the pot with a big drain hole at the bottom. Do not soak this plant until it is reestablished in the new potting soil, in a new pot. Try to keep plants in one place, to move them to less sun or more sun, drafts, no drafts...can severely weaken or kill plants.
A picture of the root system would be great as you transplant your plant. If this plant is root bound, what soil is left is unable to hold enough water long enough for the plant to uptake the water. If you've been over watering there is a big possibility the roots are rotting and not able to up take water or chemistry. If you've been underwatering you'll see the same symptoms yet this plant should have viable roots to take up the water. This is a succulent and they store their own water supply in their leaves. They NEED drought conditions in between shallow watering.