If you have a stable, well-healed, chin implant in place, infection from an external source such as a common cold virus is generally not possible. Treat your symptoms accordingly.
Even with bacterial infections such as strep throat, tonsil or tooth abscess, ear infection, or urinary tract infection (to name a few examples), secondarily infecting a completely-healed chin implant is very rare, though theoretically possible. Antibiotic therapy for the primary infection should satisfactorily protect your chin implant, but if you note increasing redness, pain, or swelling around your chin implant, you should see your surgeon. Some doctors even recommend that their implant patients take a dose or two of antibiotic as a preventive measure just before dental work (which releases significant numbers and kinds of bacteria into the blood stream) or any other procedure that might cause bacteria to enter the blood stream. I do recommend this for my breast implant patients, even though the ADA (American Dental Association) has recently relaxed their criteria for prophylactic antibiotics prior to dental work. For solid, non-mobile implants such as chin, pec, or calf implants, once these are well-healed and stable, antibiotic prophylaxis is not needed, in my opinion.
However, if you have recently had a chin implant placed and have developed pain, redness, swelling, or drainage from your incision, you may have an infection, and will need to see your surgeon. Antibiotics may relieve your symptoms, but in most cases of true implant infection, the implant must be removed, the infection treated and cured, the tissues allowed to heal and soften, and the implant replaced. If your implant was placed via an intraoral incision, the risk of bacteria being introduced into the implant pocket is higher than if a submental (below the chin) incision is used. I prefer the latter for this reason, though it is still possible for a chin implant placed via the external incision to become infected, just less likely! I also utilize preoperative IV antibiotics, antibiotic irrigation of the implant pocket before placement, and oral antibiotics for several days after surgery. A transparent adhesive bandage is glued to the incision (which is closed with under-the-skin dissolving sutures) to prevent any bacterial introduction into the tissues as they heal and seal shut over the first few days after surgery.
Diabetics are at slight increased risk for all infections, implant or not, but I have performed many different kinds of implant placements in diabetic patients without problem. Keeping your blood sugars in tight control minimizes these risks. High blood pressure does not directly increase the risk for infection, but can increase the risk of other complications such as bleeding, heart attack, or stroke. High blood pressure should be normalized by your doctor before proceeding with any type of elective surgery. This is something that should be taken care of as part of your pre-anesthetic physician examination.
HIV patients or patients who are taking immunosuppressive drugs (such as transplant patients), as well as patients undergoing chemotherapy also have higher risk of infection, and may not be a candidate for elective implant placement in some cases.