Thanks for your question! I hope that at 3 months post-op you are enjoying your improved appearance, and understand that so long as you "behave" with your calorie intake and calories expended over this holiday season, you will continue to improve your result over the next 3-6 months!
Dry and itchy skin is a normal sign of healing, nerve regeneration, and incomplete sweat and lubrication gland recovery. Mederma is a scar-improvement preparation that many patients and surgeons like and recommend, but it could be causing some degree of your symptoms, or none at all. A trial off it for a week or so may be in order.
Otherwise, providing your skin with additional lubrication and moisture will be helpful until your scars are mature (6-12 months) and all of your skin lubrication capabilities have recovered. Some of us still have dry skin, and this time of year is particularly hard on dry skin or eczema sufferers. Your incisions are well-healed, so there is no problem with using a moisturizer of your choice to improve the dryness. Itchiness may be partially helped, but may also be part of the skin sensory nerves regenerating. The latter is helped only by time (and perhaps oral Benadryl, though this can make you drowsy and is not recommended if you operate heavy machinery, including a motor vehicle). But a dose of Benadryl at bedtime, and a good rubdown with Eucerin lotion, Vaseline Intensive Care, Nutraderm, Lubriderm, Oil of Olay, etc. can help you get over this. I also like Vitamin E oil, and recommend it to all of my patients for scar massage starting 3 weeks post-op.
This won't be forever, and by spring or summer you should be good to go, though you may still need a sunscreen on your scars if still pink. Best wishes!