You can do the longlife retreat of Amitayus, reciting the long mantra ten thousand times. If you have the initiation of White Heruka, do some retreat on that, if you can. It need only be short.
Use the blessed water that we are sending you. When you receive the blessed water, sip it several times a day, taking a few tablespoons of water each time. Visualize strongly that the blessed water is purifying all the disease completely! Vajrayogini’s pure nectar is cleansing everything, especially the lump.
I send my love and prayers.