Hello, It's understandable to be concerned about a growing concave dimple in the buttock area, especially without any known trauma or recent injections. Here are a few potential causes and recommendations: Fat Atrophy: Sometimes, localized fat loss can occur due to various reasons, including past injections, even if they were a while ago. This can lead to dimpling or indentations. Subcutaneous Nodules or Cysts: Occasionally, cysts or benign nodules under the skin can cause changes in the overlying skin, including dimpling. Connective Tissue Changes: Changes in the connective tissue can sometimes lead to indentations or dimples, though this is less common. Medical Evaluation: It would be beneficial to consult a dermatologist or plastic surgeon who can evaluate the area in person. They may recommend imaging studies or a biopsy if necessary to determine the cause. Monitoring and Documentation: Continue to monitor the dimple's size and characteristics, documenting any changes with photographs. This information will be helpful for your healthcare provider. Treatment Options: Once the underlying cause is determined, treatment options can be explored. These may include fillers, fat grafting, or other procedures to address the cosmetic concern. It's important to address any changes in your body with a healthcare professional to ensure appropriate diagnosis and management. Best regards,