Do HA fillers cause permanent shape change?

Sorry to hear that you didn't achieve your goals with the fillers.  I would recommend considering dissolving more.  Cheek injections does require quite a bit of advanced training, particularly in the anatomy of the cheek and how it responds to dynamic movement.  Certain cheek injection techniques can cause predictable changes in the static face, but untoward effects with dynamic smiling. You may want to consider getting a thoughtful assessment with an experienced plastic surgeon or dermatologist who can help you assess whether additional dissolving can help and who has a great deal of mid-face volume correction.

Normally HA fillers do not result in permanent shape change unless there was an underlying inflammatory or infectious process resulting in scar formation. It is difficult to detail further without seeing you in person, or, at a minimum before and after photos and knowing date when it was done. Best to discuss it with the practitioner who injected or seek a second opinion. Good luck.

Perhaps not all the filler was adequately dissolved?  Hard to say without being your injector and comparing your pre treatment photos to now.