There are a variety maneuvers that can enlarge the alar base depending on the the shape of the other structures. This has to be considered at least a year after the initial surgery. You may wish to seek your surgeon's advice and explore the options in this regard.
You need to discuss your concerns with your surgeon. This is early for you to be concerned and your surgeon is the best qualified to answer your questions. To enlarge small nostrils is difficult ,bur not impossible. It may require the use of grafts that might need to include cartilage. Sometimes a local flap of tissue can be used but it might increase the scarring at the base of the nostril. The nostrils can be enlarged under local anesthesia if it is necessary to have surgery. The tip could also be enlarged. Give yourself at least 6 months if not a year before you do anything.
Reversing an alar base reduction can be much more complex and unpredictable than performing one. It is best for surgeons to err on the side of conservative resection, and this holds true for most aspects of rhinoplasty. Follow up with your surgeon to discuss your concerns.
It is important to be patient at this point. As with any rhinoplasty procedure, you will not likely to see your final results for 9 months, or longer. In the long-term, the actual nasal width changes very little with alar base reduction. However, it may seem so at this point. In regards to the nasal tip, it is just as important to be patient for now, your nose is likely to continue to change over the next 6 months. As always, it is important to communicate your concerns with your Plastic Surgeon.