For the creasing I recommend setting it with a powder I like Mac emphasized or Laura Meicer translucent powder it should help! With the dark circles have you tried a color corrector before the concealer like la girl or ysl came out with some recently, hope this helps!!
If you have a lot of creases under your eye then there's not much you can do. But try looking up when blending the concealer in to the skin, I dab/pat it in with my dior #12 brush. It covers dark circles great