Scar revision after Mohs surgery
There are many different treatments of unsighlty post op scars, I would suggest you discuss options with a plastic surgeon.
Reducing scarring post Mohs surgery and flap
It sounds like you had a extensive skin cancer on your nose requiring a forehead flap to help cover the area the skin cancer occupied. These flaps often do heal with some puffiness and often need revision. Often times these forehead flaps can be trimmed during revision surgery to help reduce the puffiness and size of the flap. Other options include laser resurfacing and if there are any focal areas of increased scar tissue, local steroid injections. Best to follow back up with your Mohs surgeon to discuss.
Improve Scarring after Reconstructive Surgery
Your best options is to meet with the surgeon who did the repair and tell him/her about your concerns. Based on your description (asymmetry, puffiness, larger nose), your best option is likely for another surgical procedure or revision of the scar. Topical medications and lasers may help soften or improve fine scars or dilated blood vessels, but when there is asymmetry or size or shape problems the best option is to have a revisional surgery. These types of surgeries are not unusual especially for particularly large defects or difficult repairs. Speak to the surgeon. Good luck.