How can I prevent incisions scars when I go for a round 2? (photo)

Unfortunately, you must cut the skin to make access points to do both the liposuction and the fat transfer in a BBL. When you cut the skin, there will be a scar 100% of the time. Scars differ depending on your genetics. Darker skin patients tend to scar thicker and darker. Asian patients typically do not scar "pretty". There are also many forms of scar therapy/lasers that you can purchase post op to help. Scars do fade over time and tend to look better at one year or longer after surgery. Finding a PS that chooses discrete placement of the scars really helps so that the majority of clothing/ swimmer hides the scars. 

Hi and welcome to our forum!
Unfortunately, any incision into the skin will cause a scar. In cosmetic surgery, we try to place scars in inconspicuous locations. The method of wound closure affects the appearance of a scar. The presence of postoperative infection affects a scar. Sun exposure to a healing scar may cause pigmentary change.  Scars may take 6-24 months to lose postoperative scar redness. Some individuals have a tendency toward thick scarring. Your surgeon may use the same incisions as in the previous procedure. 
We recommend intensive early wound management until the sites are sealed, later use of a moisturizer, a sunscreen when outdoors, application of silicone gel sheeting if a previous scar former, and tincture of time. 
Best wishes...