This is the chance to cultivate and practise the brahmavihara of equanimity (upekkha), in addition to compassion (karuna).
From The Four Sublime States by Ven. Nyanaponika, where he discusses the relationship between equanimity and compassion:
Equanimity rooted in insight is the guiding and restraining power for
the other three sublime states. It points out to them the direction
they have to take, and sees to it that this direction is followed.
Equanimity guards love and compassion from being dissipated in vain
quests and from going astray in the labyrinths of uncontrolled
emotion. Equanimity, being a vigilant self-control for the sake of the
final goal, does not allow sympathetic joy to rest content with humble
results, forgetting the real aims we have to strive for.
Equanimity, which means "even-mindedness," gives to love an even,
unchanging firmness and loyalty. It endows it with the great virtue of
patience. Equanimity furnishes compassion with an even, unwavering
courage and fearlessness, enabling it to face the awesome abyss of
misery and despair which confront boundless compassion again and
again. To the active side of compassion, equanimity is the calm and
firm hand led by wisdom — indispensable to those who want to practice
the difficult art of helping others. And here again equanimity means
patience, the patient devotion to the work of compassion.
How to practise equanimity?
Firstly, have confidence in your good deeds and intentions.
If, however, fear or uncertainty should arise, we know the refuge
where it can be allayed: our good deeds (kamma-patisarana). By
taking this refuge, confidence and courage will grow within us —
confidence in the protecting power of our good deeds done in the past;
courage to perform more good deeds right now, despite the discouraging
hardships of our present life. For we know that noble and selfless
deeds provide the best defense against the hard blows of destiny, that
it is never too late but always the right time for good actions.
Secondly, let go association with the self:
The second insight on which equanimity should be based is the Buddha's
teaching of no-self (anatta). This doctrine shows that in the
ultimate sense deeds are not performed by any self, nor do their
results affect any self. Further, it shows that if there is no self,
we cannot speak of "my own." It is the delusion of a self that creates
suffering and hinders or disturbs equanimity. If this or that quality
of ours is blamed, one thinks: "I am blamed" and equanimity is shaken.
If this or that work does not succeed, one thinks: "My work has
failed" and equanimity is shaken. If wealth or loved ones are lost,
one thinks: "What is mine has gone" and equanimity is shaken.
To establish equanimity as an unshakable state of mind, one has to
give up all possessive thoughts of "mine," beginning with little
things from which it is easy to detach oneself, and gradually working
up to possessions and aims to which one's whole heart clings. One also
has to give up the counterpart to such thoughts, all egoistic thoughts
of "self," beginning with a small section of one's personality, with
qualities of minor importance, with small weaknesses one clearly sees,
and gradually working up to those emotions and aversions which one
regards as the center of one's being. Thus detachment should be