Does the fact I suffer from allergies make me more prone to rejecting the implants? Please help me with other anxious thoughts.

If you are going to have this procedure, you must keep a positive attitude.  If your medical doctor has medically cleared you for surgery and you have chosen a reputable surgeon with lots of experience in the procedure, you should do quite well.  Be sure to choose a Board Certified Plastic Surgeon who specializes in this procedure and is well respected in the medical community for it.  

Butt implant surgery requires skill to create a nice uniform pocket.  The size and placement of the implant has a lot to do with possible complications.The key to this surgery is to select an implant that is not so large that the muscle cannot cover it reliably. You want a nice result, but you want to avoid the complications (need for removal, infection, extrusion, fluid collection, implant migration, implant visibility, and capsular contracture among others).  Having allergies should not cause you to worry about the risk of a foreign body reaction.Kenneth Hughes, MD, ABPS Board Certified Plastic SurgeonLos Angeles, CA

As of this day, silicone implants are considered to be completely inert, meaning the human body does not mount a true immune rejection response to/against them. That being said, there are reports of an extremely small amount women with breast implants having symptoms of “bii”, however nothing yet proven. As far as buttock implants, no reports similar to bii exist.  Please note one last but very important difference, buttock implants are made of semi-solid silicone rubber material which cannot rupture or leak into the body like silicone gel breast implants can. Hope this helps.