Near the end of the movie, when Artemisia breaks down her outdoor studio, her hands have healed, so the bandages are gone. But then, when she goes to Tassi's house and in all scenes thereafter, the bandages are still there and bleeding.
Note the inoculation scar on her lover's bicep (story was set in 1610).
The painting displayed at the trial, Judith Decapitating Holofernes, was painted c. 1618, 6 years after the 1612 trial of Tassi. The self-portrait she shows Tassi was painted in the 1630's, long after she met Tassi.