Can i get sepsis from a blister? how rate is it?

It's possible: Possible, but not likely. If the blister has ruptured, just use soap and water to clean it, and apply a protective bandage. Hand sanitizer may also be used, but will be irritating. Just keep it clean, and you should be fine.

Low risk: While technically anything can go from a minor cut or break in the skin to overwhelming infection...its is a pretty rare event. I wouldn't spend too much time worrying about this.