There is a provisional aspect to every cure. The charismatic movement in these later years has also emphasized prayers for healing and healing services among many Christians, among them many Catholics. In some cases the Sacrament of the Anointing of the Sick is conferred during these Masses. As you note from your own experience, not all those who attend such Masses or pray for healing are physically cured or made whole. But then, not everyone who goes on pilgrimage to Lourdes is miraculously cured.
Miracle cures are by their nature exceptional.
But note that those who fail to obtain physical cures at Lourdes often speak of a kind of spiritual healing, a new peace and acceptance. Surely there is a grace in the prayers and support of those who gather to pray with and for the sick. We do know that in the Gospels Christ responded to, and often demanded, the faith of people asking for healing. We also know that we cannot view prayer as granting us an entitlement of some kind. Prayers aren't magical formulas, as if you could say the right words often enough and get what you want.