Concerns about my witch/ptosis chin. Could Botox help reduce this, or would surgery be a better option? (Photo)

Robust HA volumizing fillers work well for making a pointy chin more broad and less pointy. Additionally, a robust HA Lifting filler can be used to elevate the "mental crease," the horizontal furrow between the chin and the lower lip. By doing so, once again the chin itself will appear less projecting and pointy.
Botox in the chin is best reserved for cases where the chin becomes more dimpled with expression, which is a dynamic, rather static issue as are the chin projection and mental crease.
You would be wise to consult with an experienced, board certified cosmetic dermatologist filler expert. Best of luck.