I Want to Change A Material on a Character's Face Then Change it Back for blink effect.

I have a Third person character that i want to change the material on his face to make a Blink effect. I am New to UE 4 so i know im not doing something simple most likely. Here is the code i assembled.
222123-

Anyone that can help?

I believe this is what you’ll want to do. Set the material for the BP Component, that is the character’s skeletal mesh. Find out which index number the material for his face is set to and put that in there under Element Index. Next, select the material you want it to change to.

I put in a delay, for example, that after a half second it will change to a new material, then delay half a second again, and loop back through.

Thanks alot i got a Better understanding. But you didnt use the construction script to do this?

Thanks for your help i decided to go with Flipbook instead much what i want to happen! Made things much easier i no longer need help thanks alot.