Probably not the answer, but could it be
some type of alcoholic beverage?
When you go, I may show.
Alcohol is a common item in stores and restaurants.
You fear me.
People addicted to alcohol might fear it or the effect it has on them
I'll blast if you're fast.
You're supposed to slowly drink some alcoholic beverages, especially strong ones.
You'll hear me.
Not totally sure about this one...maybe it has to do with the sound of pouring another drink?
You'll get a balloon...
A balloon can also mean "a large rounded drinking glass, used for brandy and other drinks."
...and very soon, someone will come and clear me.
This could refer to a bartender coming to pick up your glass when you've finished.