If my body rejects piercings, will it put me at a higher risk for cc?

I am not aware of any documentation that patients who have an allergic reaction to piercing also have a higher risk of capsular contractions. 

Sadly, it is impossible to predict who is at risk for capsular contracture. However, your skin sensitivity shouldn't put you at a higher risk than anyone else. I am assuming that you've shared your concerns with your surgeon. If not, make sure that you do so. Good luck with your breast augmentation in December. I'm sure they're going to look great!

Skin sensitivity to certain metals (usually nickle) has no bearing on capsular contracture.  Scar tissue associated with the skin is a different process than scar tissue tightening around an implant.