I'm sorry you have had to undergo a second operation to achieve the degree of lift you wanted and apparently needed. Your incision does not look infected, but there are incompletely-healed areas that could become infected as they are still open and normal circulation is not yet restored to these areas, which is why they have had difficulty healing thus far. This is not uncommon, and your surgeon needs to not only reassure you, but give advice to keep this from turning into a problem.
Some practical hints: If you are a smoker, or even exposed to second-hand smoke, you MUST discontinue this immediately. As I noted above, the inverted-T area of a Wise-pattern (anchor pattern) mastopexy is the area of least-robust circulation. Because of this the vertical scar actually heals with the finest and least-visible scar, BUT first it must heal. It can't do so without circulation. If you're not smoking or around smokers, or using nicotine patch, spray, gum, etc., good for you. If you are, stop IMMEDIATELY! But this area is still partially open, and susceptible to becoming infected.
Keep these areas clean. If OK with your surgeon, wash gently with soap and water (not hydrogen peroxide), pat dry, and keep a clean gauze dressing on the incisions. I'd advise NO antibiotic ointment, especially triple antibiotic ointment (such as Neosporin or Mycitracin). No ointment at all because chronic use can cause the wound to soften and separate further, and can (with chronic use) even stimulate an allergic reaction, which "looks" like an infection. So you use MORE ointment and it gets worse, not better! (Because it's an allergic reaction, NOT an infection). Triple antibiotic only gives you 3 times the likelihood of stimulating an allergic reaction, so cleanliness is better than gooping-up with antibiotic ointment. No hydrogen peroxide because it not only kills germs, but also inhibits epithelial cell growth and can actually slow healing. The exception can be an actually purulent (pus) wound, but then only once or twice with peroxide until it's clean.
Although it truly does not look infected, the tissues are compromised, which is to say that they are more susceptible to infection than the other areas of your incisions that are nicely intact and further along in their healing. So, while I am stressing that I am NOT recommending oral antibiotics because I think there is an infection here, I would recommend a broad-spectrum antibiotic to MINIMIZE the chances for these areas of incomplete healing to become infected. Just good common sense precaution, IMHO. If implants are involved, this is even more critical, to minimize potential contamination/infection that would require removal.
If fever, chills, or purulent drainage is noted, this should be cultured by your surgeon and appropriately-chosen antibiotic treatment instituted promptly (which might mean a change from the "prophylactic" antibiotic recommend earlier).
Wear a lightly-supportive cotton stretch bra without underwire. Avoid lifting, straining, or activities that might stretch the breast incisions. You are only 3 weeks out from surgery so your incisions are not yet durable, and these even-less-durable areas should be checked at least weekly, or more if needed or if they change.
Although there may be slightly more scarring in these areas, you will be amazed how much better they end up than how you think today they will look when finally healed. So be patient, see your surgeon regularly, and follow his or her advice. Ask about the hints above if they disagree with your doctor's advice. Good luck!