Are there any character's in Hetalia that represent South American countries?

So far no South American country has been personified as interesting the countries histories and cultures are. Cuba may count but he's more or less part of the Central America/Caribbean than South America. So until Himaruya decides to create a personification for a South American country you'll just have to look at fan-made ones.

I don't believe that there are as of yet. Although, I personally have made fanfiction characters for Argentina and Brazil (Argentina was my first Hetalia charrie, and I used Brazil since I had an OC for Portugal).

As of now, no, there aren't any Latin American Hetalia characters, excluding Cuba, Spain, and a few draft designs for Portugal. However, there's a community on DA and LJ (even Tumblr) called "Latin Hetalia." They're a group of people who have created /amazing/ Hispanic characters, and personally, I find them much more enjoyable than actual canon characters! If you have the chance, search 'em up. They're definitely worth checking out!

The picture I've given ya are the more popular ones.

From the top starting on the left:
-Argentina (with chibi Maradona, a famous Argentine football player), Uruguay, Brazil
-Chile, Peru, Ecuador
-Colombia, Bolivia, Paraguay
-Venezuela, Northern and Southern Mexico

Image was done by kuraudia on DA~ Hope that helps, che!