The answer to your question depends on the type of infection, type of procedure being performed, and your overall health. It is important to let your surgeon know about any change in your health including recent infection so they can assess your fitness for surgery.
I agree with my colleagues. It depends why you were on antibiotics. It also depends what you are having. If there was a common upper respiratory tract infection treated with for example a "Z-pak", those typically resolve and sometimes new labs or x-rays may be needed but typically surgery can be done within 1-2 weeks. If you are having a breast implant for example then sometimes we have to be more conservative. If someone has a full blown pneumonia then it could even be a 3 month delay. There is an increased chance of bacteria getting onto the implant and causing capsular contraction or even infected implant with recent pneumonia (even walking pneumonia). I would check with your plastic surgery and also your doctor that prescribed your antibiotics if they are different doctors. Good luck!
There is no contraindication to taking antibiotics before general anesthesia. Antibiotics are routinely administered at the beginning of each surgery and do not interfere with anesthesia.Your surgeon and anesthesia provider should be aware/notified of any existing infection which is being treated prior to your elective cosmetic surgery.Best of luck,