Capsular contracture and allergy from breast implants?

There are many different medications that are used in the perioperative process that you must review to prior to attributing this to the implants.
For example, antibiotics are frequently used to irrigate the breast implant pocket. Certain preparation agents are used to sterilize your skin prior to making an incision. These are things that you may not be aware of and could be the cause of your problem.
It is highly unlikely that you are allergic to your implants and equally unlikely that you are developing a capsular contracture this early in the healing process.
You may want to consider seeing an allergist to have testing to determine the source of your allergy.
The asymmetry of your implants may be indicative of several potential situations.
Keep in close contact with your plastic surgeon and

It is highly unlikely that your rash is related specifically to your implants.  It is not to say that it is unrelated to your surgery. It could be related to any medication, cream, dressing, tape, etc.. that you have used.  It may be a good idea to see a dermatologist or allergist at this point.

Whether you had silicone or saline implants, the outer shell of the implants are made of silicone. Having an allergy to silicone is very unlikely. There are many other pieces to this puzzle. You could be allergic to suture material, latex, antibiotic ointment, tape, gauze, etc. Since you did not improve in a few days after the surgery, you stopped the ointment and the medications...all of which were absolutely correct. You are now on a prednisone (steroid) pack, which is also correct.
If your plastic surgeon has already seen you and does not think that this is an infection, I recommend you see a dermatologist as well. Good luck!