The issue should be discussed with your MO.
It also depends how you get cisplatin. If you get this just 2-3 times at a high concentration then it is more likely that even a single dose does damage. If on the other hand you get weekly infusions with a lower dosage then the possibility that you incur damage from a single dose should be reduced and should give you a better window to assess what is going on and also a single does should then be less likely to cause permanent problems.
In my opinion, if you CAN tolerate cisplatin then go with it, it has been around longer (hence more data) and appears to be more effective than carboplatin. Also, carboplatin too has its issues (WBC).

Best

Markus