The Celtic Christian tradition offers a variety of prayers that begin "Bless to me."

One such prayer follows:

Bless to me, O God,
My soul and my body;
Bless to me, O God,
My belief and my condition;
Bless to me, O God,
My heart and my speech,
And bless to me, O God,
The handling of my hand.

Using this prayer as a way to start, add a verse with particular reference to your body and your illness. For example, if I were to do this, I could add verses such as:

Bless to me, O God,
My weakened pancreas;
Bless to me, O God,
My energy and my stamina.

Create your own prayer, adding as many verses as you like, following the rhythm of the "Bless to me, O God" pattern.

— Mary C. Earle in Beginning Again