Some schools take the best subsections from all of your PCAT taken and make a composite. Some take the highest PCAT score, and some take the most RECENT PCAT score. You should search up the schools that you are interested in and check. If it's not posted on their website, I would recommend calling them and asking.
If you take the PCAT MULTIPLE times and still get a bad score then I'd recommend you start looking for a new career and saving your $200/test...unless you somehow get a waiver to take the PCAT for free, by all means keep taking it.
Remember:
0-59% = F
60-69% = D
70-79%= C
80-89% = B
90-99% = A
This is how you should really score your PCAT. Ace your PCAT ^_^