Ouch! This is not good ;-{
Sorry to say you can’t buy the pins, all you can get is a replacement connector with all of the pins. Even if you replaced the single pin the reliability of the connections is not assured when you’ve pulled off the insulator as you did here after re-threading it back on.
Given how easy it is to replace the full connector with the proper tools and technique I would just replace it. Now I’ve done tons of connectors so I have the skills, are you up to it?
I think its wise to let someone who has the proper tools and skills to do it. DIY can only go so far … Sorry ;-{