How to replace large eggs for medium in a recipe?
There’s a good chance that the difference of what will be perhaps half a tablespoon just won’t matter in the final product. You don’t say what exactly you are going to make, but if your recipe was so sensitive to minute inaccuracies, it would probably be weight-based for all ingredients, including the eggs. 

If you really feel your batter is too dry, add a small amount of liquid (milk or whatever fits your recipe) and you should be fine.