How can I remove the line/dent in my chin and reduce the curve between my bottom lip and chin? (Photos)

For unique cases where a variety of modalities could be used to treat the condition, I would suggest an in-person or virtual consultation to develop a custom and effective treatment plan. It is difficult to precisely define the best option without collecting the same information. I suggest reaching out to an expert for a consultation with surgical and non-surgical methods to get a comprehensive option. Best, Dr. Emer.

Hi, it would be better if you could also share the profile side of your lower face for a more thorough assessment and further suggestion. 
Yes, from the frontal view, there is a significant chin dimpling with marked labio-mental fold.
This could be attributed to the strong muscle over the chin (i.e mentalis muscles) as well as inborn chin bone structure.
Hence to make it better, treatment options that you could consider include, botox over chin muscle (ie mentalis muscles) to reduce the hyperactive muscle, dermal filler over chin to reduce the marked fold as well as to create a slightly more elongated chin.
Hope that answer your question. Cheers.

Hi,
 Great question and thanks for sharing your photos. The chin can be addressed in a couple of manners. Yes, filler can be done to fill in the chin itself (to increase projection and make it more proprotional in the profile view.) Filler is also sometimes used in the “mentolabial” crease. Botox can be used to the mentalis muscle of the chin to  soften the dimpling of the chin and increase projection. Surgical options for the chin include chin implants and genioplasty (surgery on the mandible “jaw bone” that contributes to your chin.) 
 Best,
Dr. Gerecci