The implied tense here is future
A clearer sentence would be "It will get even better [very soon]"
It is usually used two ways:
To say that there is something better about a situation that you probably didn't know about.
To say that a situation is even worse. In this case the mood would be sarcastic.
"I had a flat tire on the way here."
"That's too bad."
"No, wait! It gets even better. My spare tire was flat, too!"