HA dermal filler...pain after 4 weeks, should I be concerned?

Four weeks is a long time to have pain as pain that can be attributed to swelling and/or bleeding should have been gone by this time. I would go back to your physician and see what they say about this.

Emervel is a brand of hyaluronic acid fillers but it is not approved for use in the U.S. So those of us from the U.S. can only speak about fillers in general as we won't have experience with this particular filler type. Emervel also has different fillers within this brand, so I'm not sure which one you got. Any time you are having this much pain or swelling after a procedure you should seek medical assistance in person. Even though you've taken the prescription for 4 days, that may not have been enough time to combat an infection you've had for a month. While bruising and swelling are common after fillers, it should not be as bad as you are describing or for as long. I would recommend you go a few more days with the prescription and then follow up with your physician again. "This answer has been solicited without seeing this patient and
cannot be held as true medical advice, but only opinion. Seek in-person
treatment with a trained medical professional for appropriate care."