Are you getting enough fat in your diet? I know it's hard to switch to a vegan diet if you are used to something very different. You need to learn a whole new menu.
Anyway, lack of proper dietary fat can cause skin problems. Most nutritionists recommend you get about 20%-30% of calories from fat, including different types of fat (saturated, monounsaurated, polyunsaturated). In a 2000 calorie diet, that's about 45-65 grams of fat total. Good vegan sources include seeds, nuts, and (favorites of mine) avocado and tofu. One whole California avocado has about half your daily fat alotment, mostly in monounsaturated form. 90 cashews have all the fat you need, not that you could eat that many in one day, nor should you get all your fat from one source.
I might be totally off base with all this, but I thought I'd throw it out there.