Do you think infraorbital rim implants are my next step?

If you had a good experience and are happy with the filler injections, I would recommend that you keep going with what works and have additional filler injections. My recommendation is usually to go with the least invasive option which gets you to where you want to be. I would avoid implants unless you cant achieve your goals with other techniques.

Fillers and fat grafting, when done well, will give you very natural-appearing volume correction and improvement of the lid-cheek junction depression.  Infraorbital rim implants, even when done well, can sometimes produce an unnatural appearance.  If you are seeking a more permanent solution than fillers, fat grafting is a reasonable next step.  

Orbital rim implants in the proper patient is extremely effective, but based on your one photo, I doubt that you are the proper selection.

At this point fillers and fat would be more appropriate for you. Part of the issue is skin pigmentation which will not be addressed with implants, though the shadowing might improve a bit with the fillers.

Generally, I reserve orbital rim implants after complications for surgery.  One milliliter of filler is unlikely to make much of a difference on your orbital rims.  You really need 2 to 3 ml of filler on each side.  Still these treatments are likely to last one to two years.  My personal recommendation is to stay with the fillers if they are working and reserve the surgical methods for a time when the fillers are no longer getting the job done.

Your question is a good one as both fat injections and infraorbital rim implants can be used for the exact problem you are describing. Each as their own distinct advantages and disadvantages. Fat is simpler to do and has minimal recovery but may develop lumps, partial resorption and may need to be repeated. Infraorbital rim implants require a transcutaneous lower eyelid incision, have more recovery and must be carefully placed and contoured to avoid any edge show or asymmetry, but they provide a one-time permanent solution. You have to weigh the risks vs benefits of both procedures to consider your next step.