I had breast reduction 3 months ago. Have scar tissue 12:00, 6:00 @ crease of one breast. How can I get rid of them?

Ask Surgeon. Best to run your questions and concerns by your plastic surgeon. After physical examination, it is likely that he/she will have recommendations for you. Such recommendations may include the use of silicone-based products and/or injection of steroids directly into the scars. Scars tend to improve/mature over the course of the first year after surgery; scar revision surgery may be helpful also.
Myscaraway. Myscaraway silicone sheeting that you can purchase inexpensively from walgreens.
Options. You might wish to ask your surgeon about scar deactivation. This can be done by a medical acupuncturist (physician who is trained in acupuncture). It involves placing needles adjacent to scar and using electrical stimulation. Scar injection with saline and homeopathic solution can also be beneficial. Talk with your doctor. Take care.