rut roh.. I always apply concealer before foundation.
any purple, orange, yellow, peach or pink/lilac shades for undereye are usually categorized as correctors not concealers.... and they should be used before any concealer which should be a lighter and brighter shade than skin tone.
putting any type of foundation on top of concealer is sometimes not reccomended because if you use an oil free foundation, you will begin the drying process of the undereye area. If you use a cream or oil based foundation, you may get it to settle into any fine lines or to glop up. Powder foundation should never be used under the eye area as it will most certainly look cakey or gloppy... or just too exaggerated for the trends in mu today..If you need any brightening there are many brighteners and highliters made especially for the undereye area.
putting any powder on top of concealer area can also be drying -- it is actually called a desicant.. and will absorb oils and moisture in the area.. there are few specialized powders for such an area -- LM has one: Secret Brightening powder.. and some of the more expensive lines such as Chanel/YSL/Guerlain/Cle etc have powders which are ok for the undereye area as they are light and contain less talc than the less expensive brands.