If you try to sew the 4 x 4.25 block to the rest of the blocks with the same size seams, it will be a pain in the *** .
You can "cheat/compensate" by drawing the "finished" size square on the back of the block - and then use 1/8 inch seams on the skimpy sides.
1/4 of an inch on a 4 inch (finished) block is a lot.
I would redo it.