Frozen smile and soreness in the cheeks are common effects when enough dose of botox is injected on the area (nasolabial folds), but the numbness is quite unusual for Botox. Waiting for the effect of botox to wear off is the only thing you can do. Frequent smiling and other facial expressions...
If an area is repeatedly injected over time for many years, then yes it would become atrophied. In this case it would just mean the muscle would be weaker and would either, no longer require Botox or would need much less.