@xHarlock it's a hypothetical shape of a regrown tail. They really change when regrowing, after all.
BTW, one important thing along nutrition is the temperature. Since many lizards use their tails to store nutrients, loss of the tail also means that they have much less metabolic leeway when it's cold. And slowing metabolism while in active growth state isn't a good idea in the first place, so one should keep the poor patient in ample access to heat and shade, so they can regulate their state themselves. Otherwise, they won't grow no matter how much you try to feed them.