Very Swollen at Injection Site from Filler on One Side Under Lip is This Normal?

It's very common to have minor bruising/swelling after having fillers injected, you will notice more of the swelling in the mornings. Give it a full 2 weeks for the filler to settle and heal to see your final result.

Best of luck 

Swelling is normal after lip augmentation with filler, and may be asymmetric. The swelling can last for up to two weeks. I would recommend following up with your provider with any concerns, as they know the extent of your treatment. I hope this helps, and best of luck.

The lip classically swells a great deal.  One side can certainly swell more than the other; perhaps you had more filler injected on that side or tend to favor that side when you sleep.  Give it at least 2 weeks to settle down and, if you were injected less than 48 hours ago, apply ice throughout the day.

Swelling post injection shouldn't be expected to be even. Some areas may have more swelling than other areas. When the swelling settles down (at least 10-14 days after the initial injection was done) if you find you have any unevenness at that point, you can see your injector again for an evaluation and possible hyaluronidase. But swelling shouldn't be expected to be even.

"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."