Is it normal that eye trough filler can swell up again?

Hello and thank you for your question.  This is a rare, but possible side effect that is likely due to the sinus issues you are experienced.  When there is swelling in the sinuses, the lymphatic system can get backed up and create swelling.  Because hyaluronic acid fillers are hydrophilic (or water retaining) this swelling is absorbed by the filler and thus swells.  lf this is not resolved in a couple of weeks, you should see your injector and have him/her dissolve it with hyaluronidase to resolve your symptoms.  Best of luck. 

Because all hyaluronic acid fillers absorb water to some extent, anything that can cause swelling might tend to make the filler swell somewhat.  I would recommend speaking with your injector to ensure that you do not have an infection of the filler.  If the problem persists, you may need to have the filler dissolved with hyaluronidase, although, I suspect that this problem will get better once your sinus infection resolves.  

It can happen in some patients. Best to discuss with your injector. May ultimately need to be dissolved with hyaluronidase if persists.