Cheek Hollows: Rejuran or Filler, and What Are the Risks?

Hello, I am Dr. Kim Yeon-jin, Chief Physician at UHCELL Clinic Gangnam.

If your goal is to fill a hollow cheek contour, discuss whether hyaluronic acid filler is appropriate. If skin texture is your concern, first clarify the change you want. Our official Rejuran information describes it as a skin booster for concerns involving the skin barrier, fine lines, and hydration. I recommend separating these goals rather than treating them as the same outcome.

If you are considering filler for volume, recovery time is not the only issue to understand. The U.S. Food and Drug Administration (FDA), in its 2023 filler guidance, warns that unintended injection into a blood vessel can cause tissue death, vision problems including blindness, or stroke. Your decision should account for both the contour change you want and these risks.

Is your concern cheek volume or skin texture?

Start by identifying what bothers you: a hollow shape in the front or side of the cheek, or roughness and fine lines on the surface. To prepare for a consultation, I recommend pointing out the area you most want to change and describing the result you have in mind. This does not mean diagnosing the cause yourself or deciding on a procedure in advance.

Our Gangnam clinic’s official treatment information describes Rejuran as a PN (polynucleotide) skin booster and filler as a treatment that uses hyaluronic acid to supplement volume. The Rejuran information addresses skin barrier, fine-line, and hydration concerns. The filler information describes adding volume to hollow areas in the front and side of the cheeks.

What to discuss	Rejuran	Hyaluronic acid filler
Your treatment goal	Specify the skin concern you want to address, such as texture or fine lines.	Specify the cheek contour where you want to add volume.
Product details	Confirm the exact product name, ingredients, and treatment area.	Confirm the exact product name, ingredients, and conditions for use in the cheek area.
What not to infer	Information about skin texture does not establish that the product fills cheek hollows.	A volume-enhancing use does not mean the product resolves every skin-texture concern.

This distinction alone cannot determine which treatment is appropriate for you. It does, however, lead to a more useful question than which treatment is better overall: what product is being proposed for the change you want?

If volume is the priority, confirm the product and treatment area

The FDA’s 2023 guidance includes cheek augmentation among specific uses of fillers approved in the United States. It also explains that approved treatment areas and uses vary by product. This is U.S. regulatory information. It does not mean that every hyaluronic acid product used in Korea is approved for the same purpose.

I recommend asking for more than confirmation that a product contains hyaluronic acid. Ask for its name, where in your cheek it would be placed, and the purpose of using it there. Alongside the amount of volume change you want, discuss the risks in that area and the product-specific precautions.

The same clarity of purpose matters when considering Rejuran. Does “skin texture” mean fine lines, a rough surface, or hydration? Information about skin condition should not be interpreted as a promise to change cheek contours.

If both concerns matter to you, decide which is the priority. Whether to combine treatments is a separate decision. I would not treat simultaneous procedures or a particular sequence as the default before the need for each treatment and its conditions of use have been explained.

Compare duration and recovery on the same terms

When you hear how long a result may last, I recommend asking what result is being discussed. Changes in skin texture and changes in volume are different outcomes. A study’s observation period, an estimated duration of effect, and a recommended interval before another procedure are also different things. Observation through a particular time point does not establish that the effect ends then or that another treatment is required on that date.

According to the FDA’s 2023 guidance, filler duration varies with the material and injection area. Ask about the actual product and proposed placement rather than relying on a single duration for all cheek fillers. For Rejuran, too, confirm the exact product and plan, and distinguish the expected change from the timing of reassessment.

For recovery, our official Rejuran page lists 1-3 days of downtime involving raised injection bumps and bruising. This is not a guarantee that every visible mark will disappear within that period.

The FDA’s guidance explains that swelling and bruising can occur soon after filler injections, and that many reactions resolve within days to weeks. It also notes that some adverse reactions can appear weeks, months, or years later.

I recommend against comparing recovery figures from different sources as proof that one procedure always heals faster. If you have a photo session, event, or travel date, share it before choosing a treatment.

Filler vascular occlusion is different from ordinary bruising

The FDA’s 2023 guidance explains that filler unintentionally injected into a blood vessel can block the vessel and reduce blood supply to tissue. Although the likelihood is low, the consequences can include serious, permanent harm such as tissue death, vision problems, or stroke.

I want you to understand this risk separately from expected swelling or bruising. The ingredient name “hyaluronic acid” does not mean that serious risks are absent.

If any of the following occurs during or shortly after filler treatment, do not wait. Alert the medical team immediately and seek urgent medical care. The FDA advises immediate medical evaluation for these symptoms:

• Unusual pain.
• Changes in vision.
• Skin near the injection site turning white, gray, or blue.
• Possible stroke symptoms, such as sudden difficulty speaking or weakness in the face, arms, or legs.

Our official Rejuran information describes raised injection bumps and bruising. Do not interpret those examples as a complete list of possible adverse reactions or as evidence that Rejuran is safer overall than filler. I recommend reviewing the chosen product’s precautions alongside your health history.

Bring your goals and previous treatment details to the consultation

At our Gangnam clinic, Rejuran and filler are listed among our treatments. To prepare for a consultation, I recommend writing down:

• Whether cheek contour or skin texture concerns you more, and the specific area involved.
• The names of previously injected products, where and when they were injected, and any reactions afterward.
• Important upcoming dates and the time you can allow for recovery.

If you are considering filler, also share relevant health information. The FDA’s 2023 guidance recommends discussing bleeding disorders, a history of severe allergies or anaphylaxis, allergies to local anesthetics, and inflammation or infection at the treatment site before treatment. It advises delaying filler injections until active inflammation or infection is controlled. Filler safety during pregnancy or breastfeeding has not been established, so disclose either circumstance if it applies to you.

You can review our Rejuran information and filler information before your consultation. I recommend bringing two questions: “Am I trying to change cheek volume or skin condition?” and “What is the purpose of this product, and what risks should I understand?”

※ Skin reactions and recovery times vary from person to person. Please consult a medical professional for an accurate diagnosis and treatment plan.