The daughter started crying and throwing a tantrum and the mommy/her mother started regretting having spoiled the child.
When the daughter started crying and throwing a tantrum and the mommy/her mother started having second thoughts about if she did a disservice to the child by spoiling her. This way the child will go out into the world thinking it revolves around her!
In the second example, the part in which the mother "pampered the child too much" could be the first one, the part in Italics is just an additional statement.
The "throwing a tantrum" could also be replaced by "having a tantrum/having a fit" etc.