When you get more experienced you generally can figure out how to fudge one block that is short but at first I wouldn't try to do it. And if there are several blocks off but the time you get to the end of that row, you could have major trouble, it could make that row inches shorter than the next row. A good way to keep things precise is with the use of sashing between the blocks. Then you can square them all up to the same size and 1/4 isn't all that noticeable. But not all patterns would allow the use of sashing. Accuracy is the key to having things go together smoothly and it is one we are struggle with. Try taking the block apart and putting it back together.Sometimes you can join the last tow or three in a row with a scant 1/4 inch between them make it work..