Elaine, the whole unit?
You don't want to take any responsibility for your action and find fault with Anova. It's often best to think before acting. Consider that much of the top side of the unit is hollow and would retain water so your 24-hour rice treatment was likely insufficient.
If the circuit board was still damp when you tried to use it only part might function as you discovered. Water being a great conductor you might have short circuited some still-damp circuits like the water level sensor's.
Contemporary integrated circuit controls are rarely amenable to partial replacement fixes. Cheap to make and impossible to repair, welcome to the 21st Century.
Your Anova corporate support team might have better ideas, but I'd completely repack with rice or even better, silica gel. Place Anova in a sealed bag with your desiccant of choice for a week. Then try.
For its price i certainly wouldn't expect my Anova to be sealed like a Rolex.