HELP ! Do medical schools see or even accept repeated science pre-requisites?

I received a C- in my first general chemistry class at my university and was wondering whether medical schools would like it if I retake the class or not. This will sadly NOT increase my GPA because I have already taken chemistry classes after it (a sequence) and therefore according to my counselors will not be considered to balance the first time's grade and boost my GPA. In other words, I will be wasting time if I repeat and med schools don't care. However, I heard that some med schools don't take C-'s, is that true and if so does repeating a class like that is looked down upon because I should have aced it first time through or will it look good because they are seeing improvement? Thanks so much in advance!