Thank you for your detailed explanation and timeline. Masseter Botox is commonly used to slim the jawline and reduce symptoms of bruxism or TMJ, but changes in lower facial shape can sometimes raise new concerns. Based on your description, here’s what may be happening: 1. Masseter Regrowth Yes, the effects of Botox are temporary. By 4 to 6 months post-injection, the muscle typically starts to regain volume and strength. If your facial shape started to return to baseline, this could reflect masseter muscle reactivation and gradual regrowth, especially if the muscle was quite prominent before. TMJ symptoms returning is also a strong indicator that the muscle is beginning to function and grow again. 2. Jowling or Soft Tissue Descent If the area appears heavier, with sagging around the jawline or under the chin, this could suggest early jowling. Botox-induced volume loss in the masseter can sometimes unmask looseness in overlying soft tissue, particularly in individuals with minimal fat or thinner skin. When support from the masseter is reduced, the facial fat pads and skin may shift slightly downward, contributing to a less defined or altered chin/jawline contour. What’s most likely: It could be a combination of both—partial masseter regrowth along with some degree of soft tissue laxity (early jowling), which is now more apparent as the original structure is changing. Things to observe: Firmness to touch: If you feel the muscle bulking back up when clenching, it suggests regrowth. Soft or loose skin: Suggests descent of tissue more related to jowling. While the changes are frustrating, they are not uncommon and often manageable with subtle adjustments, including addressing skin laxity or rebalancing volume elsewhere.