Comment by Alex Orteza on Versatile Mage - Chapter 97

@Alex Orteza that's probably not how healing works, in fact, it's not how healing works most the time.

To continue to explain, in most stories (including this one) healing works to accelerate the natural healing process and in some cases, often stronger or better healing mages, can aid and improve the natural healing process. In some cases it is possible to re-attach/regrow limbs, but it is incredibly uncommon. Often using items with some sort of ability which essentially reminds time in some way.
Summery: if it was easy to fix then it wouldn't stay broken.

@Alex Orteza Usually healing accelerates the natural process at the lower tiers, basic magic, which assume is her limit, would be limited. Maybe she could fix spinal injuries, or create a constant healing zone at the highest stage. Doubt many healers would get the essence to reach that, but magic is not logic so who knows