worse - comparación 

worst - lo pior de todos 

They are different for the following reason:

worse is used when we want to make comparisons:

Today is raining and thundering the weather is worse today than it was yesterday.(Maybe it was cloudy, but not raining and thundering)

worst is used as a superlative to compare three or things:

John is a bad driver, but Peter is worse than John.I really don't know what to think about Alfred, he is the worst driver I've seen in my life.

(Abject?) Worst ---> Worse ---> Bad ---> Poor ---> So so/Middling/Fair/Well ---> Good ---> Better ---> Best (Perfect?).

---> Things are becoming/getting better.

alternatively,

<--- Things are becoming/getting worse.

I can teach you English and you teach me Spanish

what do you think ?