Why Is Dracaena Wrinkling?

Dracaena Wrinkling

I have never been a dracaena fan, just before I was introduced to a beautiful Dracaena Fragrans at one of my colleagues’ home. Now I know this plant is called “a Plant of Happiness” and it removes pollutants from home air.
I didn’t find Dracaena Fragrans then. But 1 month later I have already had an appealing dracaena growing in my bedroom. I knew these plants could survive such conditions as overwatering and dryness, as well as lots of light and lack of light. Thus, I was not ready for my dracaena’s trunk wrinkling.

Now I am doing my best to define why is dracaena wrinkling. A friend of mine suggested that it could have been already dead, as they start dying from the roots.

But I hope it wrinkled because of overwatering and soil acetification. If I'm right, my dracaena still can survive. I changed the soil, and water it only moderately now. I plan to bed out some grass in the same pot with my dracaena, so it can drain the soil.