Made an error setting up an osmosis experiment, wondering how I can fix it

Hello all,

In my Advanced Biology class (basically AP bio) we were setting up an osmosis experiment when you have to take 4 cylinders of potatoes and find the mass of them before you do anything. Then you put the cylinders in a solution (There are 6 beakers, 24 potato cylinders total) and leave them overnight to weigh the potatoes again, to see what the difference is and observe osmosis in action.

Unfortunately, our class was rushed through a few experiments so we messed up on this one. Instead of finding the mass of the potatoes, we found the mass of the potatoes in the solution in the beaker, which makes it so we cannot find the mass difference of the potatoes before and after.

How can we fix this? Do we have to do the whole experiment again? Can we find the mass of 4 potato cylinders and use that as our rough estimate of the original mass?

Our teacher isn't the most forgiving and understanding person in the world, so any help would be greatly appreciated. Thanks ahead of time!