So the best way is to write another calligraphy and painting.
But if the works on the site selection are precious, memorable or of high value, you can try this method:
A calligraphy work dyed with ink is slowly soaked in tea (black tea), preferably Pu 'er tea. Take it out to dry. If you feel that the ink can't cover it, soak it again until you are satisfied.
Of course, you can also dip the brush in water, draw a circle in that place with ink, and then tear it off. Find another piece of paper that is slightly bigger than the leak. Anyway, that's how I remedy it. If the painter frames it for you, it won't show up.