Botox and scars
Let me first point out that the FDA has approved Botox for specific indications. When it is used in this capacity, it is called an "off-label" use.
As Dr. Sinclair points out, if scars are aggravated or made worse by muscle action, then it would make sense that weakening the underlying muscles may improve the scar. This has been shown to be true in certain situations.
Recently there has been some evidence that very large scars (hypertrophic) or keloid scars may also benefit...