This is a rare but serious complication of filler injection. Agreeing with the previous answer I would say that this is likely an intravascular injection of the filler material which has compromised the circulation to a portion of the upper lip. Three days of vascular compromise can lead to loss of significant tissue and scar deformity. You should seek the help of a plastic surgeon immediately.
This is a complication of fillers when filler goes into a blood vessel or puts pressure on the vessel. This needs immediate treatment to increase blood flow, reverse the filler, and thin the blood. I suggest going to an well trained physician. Pain is not normal after fillers and this is a sign something is wrong. Best, Dr. Emer.
I'm concerned about vascular compromised. The tip of the nose and above lip is involved. I would see you doc immediately. It could all just be bruising but I can't be sure looking at pics. If it is vascular comprimise, immediate hyaluronidase is needed. Perhaps hyperbaric oxygen too because of the time frame. Vascular compromised needs to be recognized in less than 24 hours for best outcomes. Requiring pain medication is a sign things aren't right too.
I am concerned with the dusky color of your skin and the effect of your reaction. You need to return immediately to your treating physician for examination. It looks like there might be vascular compromise which can be serious. Please keep us posted. Best, Dr. Green
You should return to your physician or better yet an expert in injectables immediately and get hyaluronidase injected into the lips; it appears from the picture that there is either vascular occlusion or compression in this area. The skin is already starting to look as though it may blister; make sure to apply aquaphor or other emolient to the area several times per day. To avoid longer term consequences, seek treatment as soon as possible.