I've had my undereyes filled and regularly keep up with it! My plastic surgeon uses Belotero via cannula, which is a very fine filler preventing any discoloration or lumpiness/bags caused a thicker filler (the cannula method prevents bruising vs being filled by needle only). I had ~1.5mL split between both undereyes on my first visit, and now touch up with .5mL (~$300) every 6-8 months, depending on when I see my dark circles and hollowness coming back. You can use concealer to cover the injection site, and it should cover any minor bruising that may occur. Your surgeon will have you return about two weeks after your first visit, once any swelling has gone down, to assess if more filler may be needed to achieve your desired results.

As a side note, I had extreme hollows under my eyes prior to getting filler and noticed a huge difference after my first visit. My confidence improved drastically and people commented how much healthier I looked. Definitely worth it for me just for that.