Puff Pastry Advice for Quiche

I prebaked puff pastry in a 10 inch tart dish. (1st time trying this, obviously!) It shrank, so now I have crust only 2/3 of the way up the sides. Any way I can glue some of the left over (raw) pastry in a ring around the dish before adding the custard and baking? Or must I just put in my filling and add custard only to the level of the crust? It's gonna be an ugly pie, anyway, but I think it will taste good! (Mushrooms, leeks, gruyere)