How to set a Dynamic Material Instance to change textures with bone rotation?

I’m trying to do an animated 2D face for my character, changing textures with like this video:

So, I followed more or less the process they used, I made in Blender a simple character with two bones that I refer to do the swapping (eyes and mouth _controller) and 3 materials, one for the body, and two for the face, also I did an animation where the reference bones go through all faces and called it "debug". then inside Unreal I made one material with a texture parameter and set two instances of that material one for the mouth and another for the eyes.

Then I analyzed the video of the goat, and followed a bunch of tutorials that in resume told me to go into a blueprint class actor, load my skeletal mesh loaded the debug animation asset, and do the following in the construction script and in the begin play (not both at the same time… though I was desperate so I tested that too xD), that didn’t work, and when everything was plugged in the body texture on my mesh disappeared.

Then I found this tutorial when a guy changed normals through bone rotation inside an animation blueprint, so I ran to my animation blueprint and practically did the same I did in my actor one. I plugged the debug animation on the Anim Graph and it seemed to work, ( I didn’t set up the whole faces 'cause I wanted to test it first) but at the end, the textures weren’t changing and also the body material disappeared, and then I gave up :c

So any beautiful programmer, want to tell this poor 3D artist/animator, wannabe programmer, how he can animate 2D faces using a Dynamic Material? :c Thanks in advance